CN117973095A - Column foot bottom plate calculation method for steel column steel joint column foot - Google Patents
Column foot bottom plate calculation method for steel column steel joint column foot Download PDFInfo
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Abstract
The invention belongs to the technical field of steel structure design, and provides a column foot bottom plate calculation method of a steel column steel joint column foot, which comprises the following steps: s1, judging the eccentric state of the column base plate under the combined action of the axial force standard value and the bending moment standard value, if the column base is in a small eccentric state, turning to the step S2, and if the column base is in a large eccentric state, turning to the step S3; s2, calculating the calculated thickness of the column shoe bottom plate in a small eccentric state based on an allowable stress method; and S3, calculating the calculated thickness of the column shoe bottom plate in the large eccentric state based on the allowable stress method. According to the invention, the two states of small eccentricity and large eccentricity of the column base bottom plate are considered, based on an allowable stress method, and based on a plastic yield strength theory, the basic counter force is assumed to be uniformly distributed, and the calculated thickness of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value is calculated by adopting the plastic section modulus, so that the calculation workload can be greatly simplified, and the design efficiency is improved.
Description
Technical Field
The invention belongs to the technical field of steel structure design, and particularly relates to a column foot bottom plate calculation method of a steel column rigid joint column foot.
Background
The steel column base is an important node in the steel structure, and the steel column base has the function of transmitting the axial force, bending moment and shearing force at the lower end of the column to the foundation, so that the steel column and the foundation are effectively connected together, and the upper structure is ensured to bear various external forces. The column base type is divided into four types of exposed type, outsourcing type, embedded type and inserted type according to the column base position; the two kinds of hinge joint and rigid joint column foot are divided according to the stress condition.
Exposed steel column bases are commonly adopted in light steel structure houses and heavy industry plants, and multi-layer and high-layer steel frames with earthquake-proof intensity of 6 and 7 degrees and height not more than 50m can also be adopted. The exposed column base is connected with the foundation by a hinge joint and a rigid joint. The typical structure of the exposed steel column steel joint column foot is shown in fig. 1, generally comprises a steel column 1, a column foot bottom plate 2, foundation bolts 3, shear keys 4, stiffening ribs 5, grouting materials 6 and a concrete foundation 7, wherein during installation, the concrete foundation 7 is poured firstly, 4 foundation bolts 3 are embedded in the concrete foundation, shear grooves are reserved in the foundation, the shear keys 4 are welded below the column foot bottom plate 2 in a cross shape, the column foot bottom plate 2 is welded at the bottom of the steel column 1, the stiffening ribs 5 are welded between two sides of the steel column 1 and the column foot bottom plate 2, the shear keys 4 are placed in the shear grooves, the column foot bottom plate 2 and the concrete foundation 6 are fixedly connected through the 4 foundation bolts 3, and the grouting materials 6 are filled in the shear grooves for reinforcement. The steel column steel joint column foot has the function of transmitting the axial force, bending moment and shearing force at the lower end of the steel column to the foundation, so that the steel column and the foundation are effectively connected together, and the upper structure is ensured to bear various external forces. It can be seen that the calculation of the toe floor of the rigid toe is of vital importance.
At present, the existing algorithm of the column foot bottom plate of the exposed steel column rigid column foot is based on the limit state method of bearing capacity, and the basic principle is based on the following building structural load standard (GB 50009-2012)WhereinIs a structural importance coefficient (generally 1.0); design values for effects of load combinations, taken by variable load control By taking under control of permanent loadEffect design valueThe large values of the two cases should be taken, whereinFor the j-th permanent load component coefficient (1.3 or 1.5),For the ith variable load component coefficient (whereTo take charge of variable loadTaking 1.5),Design of a life adjustment factor for the ith variable load consideration (whereTo take charge of variable loadTaking the adjustment coefficient of the design service life into consideration, generally taking 1.0),For the i-th variable load combination value coefficient (the live load is generally 0.7, the wind load is 0.6),For the j-th permanent load standard valueThe calculated load effect value is used to calculate the load effect value,Is according to the ith variable load standard valueA calculated load effect value; Is the design value of the resistance of the structural member, which is the design value based on the material property ，As the yield strength value of the material properties,The coefficient of the resistance component of the material performance (the material grade is different in value). The calculation of the existing algorithm is generally carried out according to the fifth edition of the 'steel structure connection node design manual' compiled by Qin, china building industry Press, 2023, 4 months. The detailed calculation steps can be seen in the relevant regulations in '8.8.2 rigid pin design'.
However, existing algorithms suffer from the following drawbacks: 1. the existing algorithm is based on a bearing capacity limit state method, and on one hand, the effect design value of load combination is calculatedWhen the variable load control is considered, each variable load is considered as the dominant variable load to be combined, and finally, the maximum value is taken from all load combinations to be taken as the effect design value of the final load combinationThis process is very labor intensive, thereby resulting in inefficiency of the designer design; on the other hand, in calculating the design value of the resistance of the structural memberWhen the method is used, the yield strength value of the material performance and the resistance component coefficients of different material performances are required to be determined together, so that the design efficiency of a designer is influenced; 2. the calculation of the existing algorithm is generally according to the fifth edition of the 'steel structure connection node design manual' mainly compiled by Qin, on one hand, the maximum bending moment needs to be determined according to the counter force of the concrete foundation under the column base bottom plate and the supporting condition of the bottom plate, the coefficient of the bending moment needs to be determined by means of table lookup, meanwhile, the length of the compression area of the column base bottom plate needs to be solved by means of a unitary cubic equation or determined by means of map lookup, the calculation process is complex, and the design efficiency of a designer is low; on the other hand, when the thickness of the column base bottom plate is calculated, the elastic theory is based, so that the section resistance bending moment of the column base bottom plate is calculated to be smaller, the calculated thickness of the column base bottom plate is further larger, the algorithm is conservative, the cost is increased, and the economical efficiency is poor.
Disclosure of Invention
The invention aims to provide a column foot bottom plate calculation method of a steel column foot, which adopts plastic section modulus according to plastic yield strength theory and assuming uniform distribution of basic reaction force, and calculates according to different eccentric states of the steel column foot and combined with stress states of the steel column foot, so that design efficiency is improved and engineering cost is reduced on the premise of ensuring safety.
The invention provides a column foot bottom plate calculation method for a steel column rigid joint column foot, which solves the technical problems and comprises the following steps:
s1, determining the calculated eccentricity of the rigid joint column foot under the combined action of an axial force standard value and a bending moment standard value And compareAnd critical eccentricityJudging the eccentric state of the rigid pin base, ifIf the pin is in small eccentric state, the step S2 is shifted to, ifThe rigid pin is in a large eccentric state, and the step S3 is carried out,
Wherein,，
In the method, in the process of the invention,Is the standard value of the bending moment of the rigid joint column foot, which is determined by single combination of permanent load, live load and wind load,；
Is the standard value of the axial force of the rigid joint column foot, which is determined by single combination of permanent load, live load and wind load,；
S2, calculating the calculated thickness of the column shoe bottom plate in the small eccentric state based on the allowable stress method，
，
Wherein,For calculating thickness of the compression side of the column shoe bottom plate, whenIn the time-course of which the first and second contact surfaces,When (when)In the time-course of which the first and second contact surfaces,；
S3, calculating the calculated thickness of the column shoe bottom plate in the large eccentric state based on the allowable stress method，
，
Wherein,For calculating thickness of the compression side of the column shoe bottom plate, whenIn the time-course of which the first and second contact surfaces,When (when)In the time-course of which the first and second contact surfaces,，
For the calculated thickness of the tension side of the toe box floor,；
In the method, in the process of the invention,Is a standard value of bending moment generated by a steel column base under the action of permanent load,Is a standard value of bending moment generated by a steel column base under the action of live load,Is a standard value of bending moment generated by a steel column base under the action of wind load,Is a standard value of vertical axial force generated by a steel column base under the action of permanent load,Is a standard value of vertical axial force generated by a steel column base under the action of live load,Is a standard value of vertical axial force generated by a steel column base under the action of wind load,Is the bearing width of the column base bottom plate,The cantilever length of the maximum bending moment of unit width along the bending direction caused by the basic counter force of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,As a safety factor, the safety factor of the device,，When the eccentric force is small, the column base bottom plate generates compressive stress under the combined action of the axial force standard value and the bending moment standard value,Is the yield strength value of the column shoe bottom plate,Is the standard of the compressive strength of the concrete axle center,The length of the cantilever is the length of the cantilever when the maximum bending moment is caused by the basic counter force generated under the action of the standard tension value of the foundation bolt at one side of the column base bottom plate,The distribution width of the maximum bending moment generated by the standard tension value of the unilateral foundation bolt on the flange of the steel column,And the standard value of the tension force of the foundation bolt at the tension side of the column base bottom plate is obtained.
Optionally, in step S2, the calculated thickness of the column shoe bottom plate in the small eccentric state is calculated based on the allowable stress methodI.e. based on，
Wherein,The maximum effective bending moment per unit width caused by the basic counter force generated by the pressure side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value is calculated asIn the time-course of which the first and second contact surfaces,When (when)In the time-course of which the first and second contact surfaces,；
In order to calculate the maximum resisting bending moment of unit width of the compression side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,Determined by modulus of plasticity, i.e，The maximum plastic section modulus of unit width of the compression side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,。
Optionally, in step S3, the calculated thickness of the compression side of the column shoe bottom plate in the large eccentric state is calculated based on the allowable stress method, that is, based on，
Wherein,The maximum effective bending moment per unit width caused by the basic counter force generated by the pressure side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value is calculated asIn the time-course of which the first and second contact surfaces,When (when)In the time-course of which the first and second contact surfaces,；
In order to calculate the maximum resisting bending moment of unit width of the compression side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,Determined by modulus of plasticity, i.e，The maximum plastic section modulus of unit width of the compression side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,。
Optionally, in step S3, the calculated thickness of the tension side of the column shoe base plate in the large eccentric state is calculated based on the allowable stress method, that is, based on，
Wherein,For the maximum effect bending moment per unit width caused by the basic counter force generated under the action of the standard tension value of the foundation bolt on the tension side of the column base plate, the column base plate is assumed to be distributed on the steel column flange along 45 degrees in a diffusing way under the action of the standard tension value of the foundation bolt and to generate unidirectional bending on the steel column flange,；
In order to resist the bending moment maximally per unit width on the tension side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,Determined by modulus of plasticity, i.e，The maximum plastic section modulus of unit width of the tension side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,。
Optionally, the column base bottom plate generates compressive stress under the combined action of the axial force standard value and the bending moment standard value in the small eccentric stateIn which, in the process,For the calculated length of the toe box floor,The width is calculated for the toe floor.
Optionally, the bearing width of the column base bottom plateCalculated as follows:
if the steel column steel joint column foot is in a small eccentric state, ；
If the steel column steel joint column foot is in a large eccentric state,And needs to meetIn which, in the process,The distance from the center of the column base plate to the center of the tension side foundation bolt.
Optionally, the tension of the tension side foundation bolt。
Optionally, the cantilever length of the maximum bending moment of unit width along the bending direction, which is caused by the basic counter force under the combined action of the axial force standard value and the bending moment standard value of the column base bottom plate。
In the method, in the process of the invention,Is the height of the steel column,For the width of the steel column,The cantilever length of the maximum bending moment of unit width along the length direction, which is caused by the basic counter force of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value.
Optionally, the critical eccentricity。
The invention has the beneficial effects that: firstly, considering that the stress state of a steel column rigid-connection column foot under the combined action of axial force and bending moment is related to an eccentric state, when the steel column rigid-connection column foot is in a small eccentric state, axial pressure is generated on a compression side, axial tension does not occur at a tension side foundation bolt, the compression side axial pressure is resisted by bearing of a column foot bottom plate, the tension side does not need foundation bolts to resist the axial tension, when the steel column rigid-connection column foot is in a large eccentric state, the compression side can generate axial pressure, the tension side foundation bolt can generate axial tension, the compression side axial pressure is resisted by bearing of the column foot bottom plate, and the axial tension at the tension side foundation bolt is resisted by the foundation bolts, so that different calculation methods are provided according to different eccentric states of the steel column rigid-connection column foot, particularly according to standard values of the axial force of the column foot bottom plateAnd bending moment standard valueCalculating eccentricity under combined actionAnd critical eccentricityJudging the eccentric state of the rigid joint column base, calculating the calculated thickness of the pressed side of the column base bottom plate for small eccentric state, and then calculating the calculated value and the minimum thicknessSelecting maximum value, calculating the calculated thickness of the compression side and the tension side of the column base plate for large eccentric state, and then calculating the thickness of the column base plate and the minimum thicknessThe maximum value is selected in the method, so that the thickness of the column base bottom plate can be accurately calculated, and the calculation result is economical and reasonable and has high reliability;
Secondly, aiming at the defect that the design efficiency is greatly affected by calculation workload caused by various load combinations when the effect design value of the load combinations is calculated in the prior art, the invention calculates the axial force standard value of the rigid joint column foot And bending moment standard valueWhen only a single load combination of permanent load, live load and wind load is considered, i.e、The calculation workload of the standard axial force value and the standard bending moment value of the steel column foot can be greatly reduced, so that the calculation workload of the calculation eccentricity is greatly reduced, and the design efficiency is improved;
again, the invention is based on the allowable stress method, the basic principle of which is based on The left side of the inequality is the standard value of the effect of the standard combination, which is aboutWhile the invention calculates the standard value of the axial force of the rigid pin baseWhen the method is used, only a single load combination of a permanent load, a live load and a wind load is considered, so that the calculation workload is greatly reduced, the calculation workload of an effect standard value is also greatly reduced, and the design efficiency is improved; to the right of the inequality is the resistance yield strength value of the structural member, which is determined by the yield strength value of the material properties (i.e., the yield strength value of the toe box floor) The method has the advantages that the determination can be carried out, the calculation workload of the resistance yield strength value can be greatly reduced, the whole calculation process is further greatly simplified, and the design efficiency of designers is improved; at the same time, the invention introduces a safety factorAnd a fixed value of 1.5 is given to the safety reserve, so that the safety reserve can be improved;
Finally, the invention considers that the column foot bottom plate is plastically damaged under the load action of the lower end of the steel column, so that the calculation thickness of the column foot bottom plate can be optimized by adopting the plastic section modulus according to the plastic yield strength theory when calculating the bending stress of the column foot bottom plate under the load action of the lower end of the steel column, the engineering cost is reduced on the premise of ensuring the safety, and the economy is better.
Drawings
The invention will be further described with reference to the accompanying drawings and examples, in which:
FIG. 1 is a schematic view of an exposed steel column steel pin according to an embodiment of the present invention;
FIG. 2 is a flow chart of an embodiment of the present invention;
FIG. 3 is a graph of calculated section of maximum bending moment of the sole of the column in an embodiment of the invention;
FIG. 4 is a diagram of a small eccentricity of the sole of the column in an embodiment of the present invention;
FIG. 5 is a diagram of a large eccentricity of the sole of a column in an embodiment of the present invention;
FIG. 6 is a distribution diagram of the load spread of an anchor bolt in an embodiment of the present invention.
In the figure: 1-steel column, 2-column foot bottom plate, 3-rag bolt, 4-shear key, 5-stiffening rib, 6-grouting material and 7-concrete foundation.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The method for calculating the column shoe bottom plate of the steel column shoe of the present invention will be described with reference to fig. 1 to 6.
As shown in fig. 2, the invention provides a column foot bottom plate calculating method of a steel column foot, which comprises the following steps:
s1, determining the calculated eccentricity of the rigid joint column foot under the combined action of an axial force standard value and a bending moment standard value And compareAnd critical eccentricityJudging the eccentric state of the rigid pin base, ifIf the pin is in small eccentric state, the step S2 is shifted to, ifThe rigid pin is in a large eccentric state, and the step S3 is carried out,
Wherein,，
In the method, in the process of the invention,Is the standard value of the bending moment of the rigid joint column foot, which is determined by single combination of permanent load, live load and wind load,；
Is the standard value of the axial force of the rigid joint column foot, which is determined by single combination of permanent load, live load and wind load,；
S2, calculating the calculated thickness of the column shoe bottom plate in the small eccentric state based on the allowable stress method，
，
Wherein,For calculating thickness of the compression side of the column shoe bottom plate, whenIn the time-course of which the first and second contact surfaces,When (when)In the time-course of which the first and second contact surfaces,；
S3, calculating the calculated thickness of the column shoe bottom plate in the large eccentric state based on the allowable stress method，
，
Wherein,For calculating thickness of the compression side of the column shoe bottom plate, whenIn the time-course of which the first and second contact surfaces,When (when)In the time-course of which the first and second contact surfaces,，
For the calculated thickness of the tension side of the toe box floor,；
In the method, in the process of the invention,Is a standard value of bending moment generated by a steel column base under the action of permanent load,Is a standard value of bending moment generated by a steel column base under the action of live load,Is a standard value of bending moment generated by a steel column base under the action of wind load,Is a standard value of vertical axial force generated by a steel column base under the action of permanent load,Is a standard value of vertical axial force generated by a steel column base under the action of live load,Is a standard value of vertical axial force generated by a steel column base under the action of wind load,Is the bearing width of the column base bottom plate,The cantilever length of the maximum bending moment of unit width along the bending direction caused by the basic counter force of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,As a safety factor, the safety factor of the device,，When the eccentric force is small, the column base bottom plate generates compressive stress under the combined action of the axial force standard value and the bending moment standard value,Is the yield strength value of the column shoe bottom plate,Is the standard of the compressive strength of the concrete axle center,The length of the cantilever is the length of the cantilever when the maximum bending moment is caused by the basic counter force generated under the action of the standard tension value of the foundation bolt at one side of the column base bottom plate,The distribution width of the maximum bending moment generated by the standard tension value of the unilateral foundation bolt on the flange of the steel column,And the standard value of the tension force of the foundation bolt at the tension side of the column base bottom plate is obtained.
In one embodiment, in step S2, the calculated thickness of the toe plate in the small eccentric state is calculated based on the allowable stress methodI.e. based on，
Wherein,The maximum effective bending moment per unit width caused by the basic counter force generated by the pressure side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value is calculated asIn the time-course of which the first and second contact surfaces,When (when)In the time-course of which the first and second contact surfaces,；
In order to calculate the maximum resisting bending moment of unit width of the compression side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,Determined by modulus of plasticity, i.e，The maximum plastic section modulus of unit width of the compression side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,。
In one embodiment, in step S3, the calculated thickness of the pressure side of the column shoe sole plate in the large eccentric state is calculated based on the allowable stress method, that is, based on，
Wherein,The maximum effective bending moment per unit width caused by the basic counter force generated by the pressure side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value is calculated asIn the time-course of which the first and second contact surfaces,When (when)In the time-course of which the first and second contact surfaces,；
In order to calculate the maximum resisting bending moment of unit width of the compression side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,Determined by modulus of plasticity, i.e，The maximum plastic section modulus of unit width of the compression side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,。
In one embodiment, in step S3, the calculated thickness of the tension side of the toe plate in the large eccentric state is calculated based on the allowable stress method, that is, based on，
Wherein,For the maximum effect bending moment per unit width caused by the basic counter force generated under the action of the standard tension value of the foundation bolt on the tension side of the column base plate, the column base plate is assumed to be distributed on the steel column flange along 45 degrees in a diffusing way under the action of the standard tension value of the foundation bolt and to generate unidirectional bending on the steel column flange,；
In order to resist the bending moment maximally per unit width on the tension side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,Determined by modulus of plasticity, i.e，The maximum plastic section modulus of unit width of the tension side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,。
The invention is designed based on the allowable stress method, so that the calculation workload can be greatly simplified, and the calculation thickness of the column base plate can be optimized by adopting the plastic section modulus according to the plastic yield strength theory when the column base plate is calculated to generate bending stress under the load action of the lower end of the steel column, so that the engineering cost is reduced on the premise of ensuring the safety, and the economy is better.
In one embodiment, as shown in FIG. 4, in the small eccentric state of the toe box floor, the tension side anchor bolts of the toe box floor do not generate tension, and thus the toe box floor generates compressive stress under the combined action of the standard axial force value and the standard bending moment valueIn which, in the process,For the calculated length of the toe box floor,For calculating the width of the column base bottom plate, the invention calculates the standard value of the axial force of the rigid column baseOnly a single load combination of permanent load, live load and wind load is considered, so that the calculation workload is greatly reduced, and the calculation workload is also greatly reducedThe design efficiency is further improved.
In one embodiment, the invention calculates the bearing width of the column shoe bottom plateWhen the method is used, the method does not need to solve by means of a unitary cubic equation or determine by means of image checking, but calculates according to the following formula, and the calculation process is simple, so that the method is beneficial to improving the design efficiency of designers, and specifically comprises the following steps:
if the steel column steel joint column foot is in a small eccentric state, the stress condition of the column foot bottom plate in the small eccentric state is shown in fig. 4, and the tension side foundation bolt of the column foot bottom plate does not generate tension at the moment, as can be seen from fig. 4 and static balance I.e. the bearing width of the column base plate；
If the steel column steel joint column foot is in a large eccentric state, the stress condition of the column foot bottom plate in the large eccentric state is shown in figure 5, and the compressive stress is at the momentHas reachedThe column shoe bottom plate is pulled by the side anchor bolts, and thus,
，
The method is characterized in that the method is obtained after the simplified solution: And needs to meet In which, in the process,The distance from the center of the column base plate to the center of the tension side foundation bolt. Because the invention calculates the standard value of the axial force of the rigid joint column footOnly a single load combination of permanent load, live load and wind load is considered, so that the calculation workload is greatly reduced, and the calculation workload is also greatly reducedThe design efficiency is further improved.
In one embodiment, the stress condition of the column base plate in the large eccentric state is shown in FIG. 5, and the compressive stress is generatedHas reachedThe tension side foundation bolt of the column base bottom plate generates tension, and the tension of the tension side foundation bolt can be known from the figure 5 and the static balance. Because the invention calculates the standard value of the axial force of the rigid joint column footOnly a single load combination of permanent load, live load and wind load is considered, so that the calculation workload is greatly reduced, and the calculation workload is also greatly reducedThe design efficiency is further improved.
In the prior art, the maximum bending moment caused by the basic counter force generated by the column foot bottom plate under the combined action of the axial force standard value and the bending moment standard value is based on the rigid constraint of the column foot bottom plate by the steel column, and the steel column can not reach the complete rigidity although the constraint of the column foot bottom plate is very strong, so that the maximum bending moment calculated by the prior art is smaller and has deviation with the actual situation, therefore, in one embodiment, as shown in figure 3, the invention introduces the maximum bending moment calculation section line which can reasonably reflect the critical section of the column foot bottom plate which generates bending under the combined action of the axial force standard value and the bending moment standard value, and can more accurately calculate the cantilever length of the column foot bottom plate when calculating the bending moment under the combined action of the axial force standard value and the bending moment standard value according to the critical sectionAnd then more accurately calculate the maximum bending moment generated by the column foot bottom plate under the combined action of the axial force standard value and the bending moment standard value, thereby reasonably designing the column foot bottom plate. Thus, in one embodiment, the cantilever length of the column shoe base plate in the bending direction per unit width of the maximum bending moment caused by the basic counter force under the combined action of the axial force standard value and the bending moment standard valueIn which, in the process,Is the height of the steel column,For the width of the steel column,The cantilever length of the maximum bending moment of unit width along the length direction, which is caused by the basic counter force of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value.
In one embodiment, the critical eccentricityBecause the invention calculates the standard value of the axial force of the rigid joint column footOnly a single load combination of permanent load, live load and wind load is considered, so that the calculation workload is greatly reduced, and the calculation workload is also greatly reducedThe design efficiency is further improved.
The invention is based on allowable stress, according to the plastic yield strength theory, assuming that basic counter force is uniformly distributed, adopting plastic section modulus, simultaneously calculating the calculated thickness of the column foot floor aiming at different eccentric states of the steel column foot and combining the stress states, and specifically comprises the following steps:
S1, judging the eccentric state of the rigid joint column foot under the combined action of an axial force standard value and a bending moment standard value, wherein the calculation steps are as follows:
S101, calculating the axial force standard value of the rigid joint column foot And bending moment standard valueCalculated as follows:
(1-1)
in the method, in the process of the invention, Is a standard value of vertical axial force generated by a steel column base under the action of permanent load,Is a standard value of vertical axial force generated by a steel column base under the action of live load,The standard value of the vertical axial force generated by the steel column base under the action of wind load is set;
(1-2)
in the method, in the process of the invention, Is a standard value of bending moment generated by a steel column base under the action of permanent load,Is a standard value of bending moment generated by a steel column base under the action of live load,The standard value of the bending moment generated by the steel column base under the action of wind load is used;
S102, calculating the standard value of the on-axis force of the rigid connection column foot And bending moment standard valueCalculating eccentricity under combined actionCalculated as follows:
(1-3)
S103, according to the calculated eccentricity And critical eccentricityThe eccentric state of the rigid column foot is judged according to the following relation:
Is in a small eccentric state (1-4)
Is in a large eccentric state (1-5)
If the rigid post base is in a small eccentric state, the step S2 is carried out, and if the rigid post base is in a large eccentric state, the step S3 is carried out;
S2, calculating the calculated thickness of the column shoe bottom plate in the small eccentric state based on the allowable stress method The specific calculation steps are as follows:
S201, calculating the maximum effective bending moment per unit width caused by the basic counter force generated by the pressure side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value Calculated as follows:
When (when) In the time-course of which the first and second contact surfaces, (2-1)
When (when)In the time-course of which the first and second contact surfaces, (2-2)
In the method, in the process of the invention,The cantilever length of the maximum bending moment of unit width along the bending direction caused by the basic counter force of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,When the eccentric force is small, the column base bottom plate generates compressive stress under the combined action of the axial force standard value and the bending moment standard value,The bearing width of the column base bottom plate is;
S202, calculating the maximum unit width resisting bending moment of the pressed side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value Calculated as follows:
(2-3)
in the method, in the process of the invention, Is the yield strength value of the column shoe bottom plate,The maximum plastic section modulus of unit width of the column base bottom plate pressure side under the combined action of the axial force standard value and the bending moment standard value is calculated according to the following formula:
(2-4)
substituting formula (2-4) into formula (2-3) yields the following formula:
(2-5)
S203, calculating the calculated thickness of the compression side of the column base bottom plate based on the allowable stress method The method comprises the following steps:
(2-6)
in the method, in the process of the invention, As a safety factor, the safety factor of the device,；
Substituting formula (2-1), formula (2-2) and formula (2-5) into formula (2-6) gives the following formula:
When (when) In the time-course of which the first and second contact surfaces, (2-7)
When (when)In the time-course of which the first and second contact surfaces, (2-8)
The following formulas are obtained by simplifying the formulas (2-7) and (2-8):
When (when) In the time-course of which the first and second contact surfaces, (2-9)
When (when)In the time-course of which the first and second contact surfaces, (2-10)
S204, determining the calculated thickness of the column base bottom plateCalculated as follows:
(2-11)，
In the formula (2-11) Taking the minimum value of the formula (2-9) or (2-10);
S3, calculating the calculated thickness of the column shoe bottom plate in the large eccentric state based on the allowable stress method The specific calculation steps are as follows:
s301, calculating the maximum effective bending moment per unit width caused by the basic counter force generated by the pressure side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value Calculated as follows:
When (when) In the time-course of which the first and second contact surfaces, (3-1)
When (when)In the time-course of which the first and second contact surfaces, (3-2)
In the method, in the process of the invention,Is the standard of the compressive strength of the concrete axle center,The cantilever length of the maximum bending moment of unit width along the bending direction caused by the basic counter force of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,The bearing width of the column base bottom plate is;
S302, calculating the maximum unit width resisting bending moment of the pressed side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value Calculated as follows:
(3-3)
in the method, in the process of the invention, Is the yield strength value of the column shoe bottom plate,The maximum plastic section modulus of unit width of the column base bottom plate pressure side under the combined action of the axial force standard value and the bending moment standard value is calculated according to the following formula:
(3-4)
Substituting formula (3-4) into formula (3-3) yields the following formula:
(3-5)
s303, calculating the calculated thickness of the compression side of the column base bottom plate based on the allowable stress method The method comprises the following steps:
(3-6)
in the method, in the process of the invention, As a safety factor, the safety factor of the device,；
Substituting formula (3-1), formula (3-2) and formula (3-5) into formula (3-6) gives the following formula:
When (when) In the time-course of which the first and second contact surfaces, (3-7)
When (when)In the time-course of which the first and second contact surfaces, (3-8)
The following formulas are obtained by simplifying the formulas (3-7) and (3-8):
When (when) In the time-course of which the first and second contact surfaces, (3-9)
When (when)In the time-course of which the first and second contact surfaces, (3-10)
S304, calculating the maximum effective bending moment of unit width caused by basic counter force generated under the action of the standard tension force of the foundation bolt at the tension side of the column base bottom plateAs shown in fig. 6, it is assumed that the toe bottom plate is spread on the steel column flange at 45 deg. under the effect of the standard value of the anchor bolt tension and is unidirectionally bent on the steel column flange,Calculated as follows:
(3-11)
in the method, in the process of the invention, The length of the cantilever is the length of the cantilever when the maximum bending moment is caused by the basic counter force generated under the action of the standard tension value of the foundation bolt at one side of the column base bottom plate,The distribution width of the maximum bending moment generated by the standard tension value of the unilateral foundation bolt on the flange of the steel column,The standard value of the tension force of the foundation bolt at the tension side of the column base bottom plate is set;
S305, calculating the maximum unit width resisting bending moment of the tension side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value Calculated as follows:
(3-12)
in the method, in the process of the invention, Is the yield strength value of the column shoe bottom plate,The maximum plastic section modulus per unit width of the tension side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value is calculated according to the following formula:
(3-13)
Substituting formula (3-13) into formula (3-12) to obtain the following formula:
(3-14)
s306, calculating the calculated thickness of the tension side of the column base bottom plate based on the allowable stress method The method comprises the following steps:
(3-15)
in the method, in the process of the invention, As a safety factor, the safety factor of the device,；
Substituting the formula (3-11) and the formula (3-14) into the formula (3-15) gives the following formula:
(3-16)
The following formula is obtained by simplifying the formula (3-16):
(3-17)
s307, determining the calculated thickness of the column base plate Calculated as follows:
(3-18)
In the formula (3-18) Taking the minimum value of the formula (3-9) or (3-10),Taking the minimum value of the formula (3-17).
The above embodiment is based on the condition that the bending moment acts along the length direction of the column shoe bottom plate, if the bending moment acts along the width direction of the column shoe bottom plate, the calculation principle of the steel column bottom plate is the same as that described above, and the parameters in the above formula are calculatedCorresponding changes to、Corresponding changes to、Corresponding changes toSo that the product can be obtained,The cantilever length of the maximum bending moment of unit width along the width direction caused by the basic counter force of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,。
The calculation method provided by the invention is used for carrying out example analysis on the column foot bottom plate of the steel column rigid column foot of a certain project.
The basic parameters of the rigid connection column base are as follows:，，，，，，，，，,。
the specific calculation steps of the invention are as follows:
firstly, determining the eccentric state of a column base plate:
Cantilever length of maximum bending moment per unit width along bending direction caused by basic counter force of column base bottom plate under combined action of axial force standard value and bending moment standard value ；
Therefore, the column shoe bottom plate is in a large eccentric state;
secondly, calculating the calculated thickness of the column shoe bottom plate in the large eccentric state based on the allowable stress method The method specifically comprises the following steps:
step 1: checking whether the inequality is established or not,
The inequality holds;
Step 2: determining the bearing width of column base plate ，
；
Step 3: determining calculated thickness of compression side toe bottom plate，
；
Step 4: determining tension of tension side anchor bolt，
；
Step 5: determining calculated thickness of tension side toe floor，
；
Step 6: determining calculated thickness of toe bottom plate，
。
For the above application embodiment, if calculated according to the prior art, the calculated thickness of the column shoe base plate is obtained as. Calculating thickness of column base bottom plate by adopting prior artGreater than the calculated thickness of the present inventionThe method has the advantages that the calculation method in the prior art is conservative, the cost is increased, the economical efficiency is poor, the design efficiency can be improved on the premise of ensuring the safety, and the engineering cost is reduced.
It will be understood that modifications and variations will be apparent to those skilled in the art from the foregoing description, and it is intended that all such modifications and variations be included within the scope of the following claims.
Claims (9)
1. The column foot bottom plate calculation method of the steel column rigid connection column foot is characterized by comprising the following steps of:
s1, determining the calculated eccentricity of the rigid joint column foot under the combined action of an axial force standard value and a bending moment standard value And compare/>And critical eccentricity/>Judging the eccentric state of the rigid pin base, if/>If the pin is in a small eccentric state, the step S2 is shifted to, if/>The rigid pin is in a large eccentric state, and the step S3 is carried out,
Wherein,，
In the method, in the process of the invention,Is the standard value of the bending moment of the rigid joint column foot, which is determined by single combination of permanent load, live load and wind load,；
Is the standard value of the axial force of the rigid joint column foot, which is determined by single combination of permanent load, live load and wind load,；
S2, calculating the calculated thickness of the column shoe bottom plate in the small eccentric state based on the allowable stress method，
，
Wherein,For the calculated thickness of the stressed side of the toe box floor, when/>Time,/>When/>In the time-course of which the first and second contact surfaces,；
S3, calculating the calculated thickness of the column shoe bottom plate in the large eccentric state based on the allowable stress method，
，
Wherein,For the calculated thickness of the stressed side of the toe box floor, when/>Time,/>When/>In the time-course of which the first and second contact surfaces,，
For the calculated thickness of the tension side of the toe box floor,/>；
In the method, in the process of the invention,Is the standard value of bending moment generated by the steel column foot under the action of permanent load,/>Is the standard value of bending moment generated by the column foot of the steel column under the action of live load,/>Is a standard value of bending moment generated by a steel column base under the action of wind load,Is a standard value of vertical axial force generated by a steel column base under the action of permanent load, and is a standard value of the vertical axial force generated by a steel column base under the action of permanent loadIs a standard value of vertical axial force generated by a steel column foot under the action of live load, and is a standard value of the vertical axial force generated by a steel column foot under the action of live loadIs a standard value of vertical axial force generated by a steel column base under the action of wind load, and is a standard value of the vertical axial force generated by a steel column base under the action of wind loadIs the bearing width of column base plate,/>The cantilever length of the maximum bending moment per unit width along the bending direction, which is caused by the basic counter force of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,/>, is thatAs a safety factor,/>，/>When the eccentric force is small, the column base bottom plate generates compressive stress under the combined action of the axial force standard value and the bending moment standard value, and the column base bottom plate is in a small eccentric stateIs the yield strength value of column base plate,/>Is the standard of compressive strength of the concrete axle center,/>For the cantilever length of the maximum bending moment caused by the foundation reaction force generated under the action of the standard tension value of the foundation bolt at one side of the column base bottom plate,/>The distribution width of the maximum bending moment generated for the single-side foundation bolt tension standard value on the flange of the steel column,/>And the standard value of the tension force of the foundation bolt at the tension side of the column base bottom plate is obtained.
2. The method for calculating a toe cap plate for a steel column steel toe according to claim 1, wherein in step S2, the calculated thickness of the toe cap plate in the small eccentric state is calculated based on the allowable stress methodI.e. based on/>，
Wherein,The maximum effective bending moment per unit width caused by the basic counter force generated by the pressure side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value is equal to the sum of the axial force standard value and the bending moment standard valueTime,/>When/>Time,/>；
In order to calculate the maximum unit width resisting bending moment of the pressure side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,/>Determined by the modulus of plasticity, i.e./>，/>The maximum plastic section modulus per unit width of the compression side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value is/>。
3. The method for calculating a column shoe bottom plate of a steel column shoe according to claim 1, wherein in step S3, the calculated thickness of the pressed side of the column shoe bottom plate in the large eccentric state is calculated based on the allowable stress method, namely, based on the following steps，
Wherein,The maximum effective bending moment per unit width caused by the basic counter force generated by the pressure side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value is equal to the sum of the axial force standard value and the bending moment standard valueTime,/>When/>Time,/>；
In order to calculate the maximum unit width resisting bending moment of the pressure side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,/>Determined by the modulus of plasticity, i.e./>，/>The maximum plastic section modulus per unit width of the compression side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value is/>。
4. The method for calculating a toe cap plate for a steel column steel toe according to claim 1, wherein in step S3, the calculated thickness of the toe cap plate in the pulled side in the large eccentric state is calculated based on the allowable stress method, that is, based on the weight of the steel column steel toe，
Wherein,For the maximum effect bending moment per unit width caused by foundation reaction force generated under the action of the standard tension value of the foundation bolt on the tension side of the column base plate, the column base plate is assumed to be distributed on the steel column flange along 45 DEG in a diffusing way under the action of the standard tension value of the foundation bolt and generate unidirectional bending on the steel column flange, and the maximum effect bending moment per unit width is assumed to be equal to the maximum effect bending moment per unit width；
For the maximum unit width resisting bending moment of the tension side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value,/>Determined by the modulus of plasticity, i.e./>，/>The maximum plastic section modulus per unit width of the tension side of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value is/are。
5. The method for calculating a column shoe bottom plate of a steel column steel joint column shoe according to claim 1, wherein the column shoe bottom plate generates compressive stress under the combined action of an axial force standard value and a bending moment standard value in the small eccentric stateIn the above, the ratio of/>For the calculated length of the column shoe bottom plate,/>The width is calculated for the toe floor.
6. The method for calculating a column shoe bottom plate of a steel column steel joint column shoe according to claim 1, wherein the column shoe bottom plate has a bearing widthCalculated as follows:
if the steel column steel joint column foot is in a small eccentric state, ；
If the steel column steel joint column foot is in a large eccentric state,And needs to meetIn the above, the ratio of/>The distance from the center of the column base plate to the center of the tension side foundation bolt.
7. The method for calculating a column shoe bottom plate of a steel column steel joint column shoe according to claim 1, wherein the tension force of the tension side anchor bolt。
8. The method for calculating a column shoe bottom plate of a steel column shoe according to claim 1, wherein the column shoe bottom plate has a cantilever length in a bending direction per unit width of a maximum bending moment caused by a basic counter force under the combined action of a standard axial force value and a standard bending moment value，
In the method, in the process of the invention,Is the height of the steel column,/>Is the width of steel column,/>The cantilever length of the maximum bending moment of unit width along the length direction, which is caused by the basic counter force of the column base bottom plate under the combined action of the axial force standard value and the bending moment standard value.
9. The method for calculating a column shoe bottom plate of a steel column steel joint column shoe according to claim 1, wherein the critical eccentricity is as follows。
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| CN114547757A (en) * | 2022-03-18 | 2022-05-27 | 湖北省工业建筑集团有限公司 | Calculation method for exposed steel column rigid connection column base |
| CN114547758A (en) * | 2022-03-18 | 2022-05-27 | 湖北省工业建筑集团有限公司 | Calculation method for exposed steel column hinged column base |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114547757A (en) * | 2022-03-18 | 2022-05-27 | 湖北省工业建筑集团有限公司 | Calculation method for exposed steel column rigid connection column base |
| CN114547758A (en) * | 2022-03-18 | 2022-05-27 | 湖北省工业建筑集团有限公司 | Calculation method for exposed steel column hinged column base |
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| Title |
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| 李雄彦 等: "Venlo型温室柱脚螺栓节点力学性能", 《农业工程学报》, vol. 40, no. 3, 29 February 2024 (2024-02-29), pages 240 - 250 * |
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