CN108399306B - Method for calculating bending bearing capacity of constant-temperature and high-temperature unified concrete filled steel tube member - Google Patents

Method for calculating bending bearing capacity of constant-temperature and high-temperature unified concrete filled steel tube member Download PDF

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CN108399306B
CN108399306B CN201810199934.0A CN201810199934A CN108399306B CN 108399306 B CN108399306 B CN 108399306B CN 201810199934 A CN201810199934 A CN 201810199934A CN 108399306 B CN108399306 B CN 108399306B
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temperature
bearing capacity
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steel pipe
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CN108399306A (en
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余敏
徐浩铭
黄伟军
叶建乔
池寅
徐礼华
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Wuhan University WHU
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Abstract

The invention provides a method for calculating the bending bearing capacity of a steel pipe concrete member unified at normal temperature and high temperature, which can simply, conveniently and directly determine the bending bearing capacity of the steel pipe concrete member in various cross section forms under the actions of normal temperature and high temperature of fire, and is characterized by comprising the following steps of: step 1, collecting relevant parameters of a concrete-filled steel tube member; step 2, respectively obtaining the average temperature of the steel pipe and the average temperature of the concrete according to the fire time; step 3, determining the design value M of the flexural bearing capacity of the steel pipe concrete member at normal temperature or high temperature according to the average temperature of the steel pipe and the concreteu,TStability factor of
Figure DDA0001594193000000012
Design value N of bearing capacity of axial compression strength0,TDesign value N of axial tension bearing capacity0t,TEuler critical force Ncr,T(ii) a Step 4, calculating the bending bearing capacity of the concrete-filled steel tube component at normal temperature or fire high temperature:
Figure DDA0001594193000000011

Description

Method for calculating bending bearing capacity of constant-temperature and high-temperature unified concrete filled steel tube member
Technical Field
The invention belongs to the technical field of steel pipe concrete in industrial and civil building structural engineering, and particularly relates to a method for calculating the bending bearing capacity of a steel pipe concrete member unified at normal and high temperature.
Background
The steel pipe concrete structure has the advantages of high bearing capacity, excellent earthquake resistance, good ductility, good fire resistance, economy, reasonability and the like, and is widely applied to structures such as bridges, high-rise and super high-rise buildings. Concrete filled steel tubes are commonly used as column members in practical applications and need to withstand the combined action of pressure and bending moment. Meanwhile, a fire disaster is one of the most vulnerable disaster forms of a building structure, and the strength and rigidity of steel and concrete are remarkably reduced along with the rise of temperature under the fire disaster, so that structural collapse is easily caused, and public safety is seriously threatened. In order to allow sufficient time for escape and fire rescue, the fire protection code of building design GB 50016-2014 specifies the fire performance and fire resistance limits of building components, and fire protection design has become an important component of structural design. For steel pipe concrete, because the steel pipe is exposed outside, the bearing capacity of the steel pipe part is lost quickly under fire, and although the internal concrete plays a certain role in absorbing heat and resisting external load, when the load is large, if no extra fireproof protection is provided, the fireproof time of the internal concrete cannot meet the requirement of the fireproof grade. Therefore, calculation of the bearing capacity of the steel pipe concrete at normal temperature and high temperature in fire is always an important research subject in the field.
At present, a plurality of methods for calculating the bending bearing capacity of the concrete filled steel tube are available, most of formulas adopted in the methods are obtained by fitting finite element calculation results, the formula forms are too complex due to excessive introduced parameters and coefficients, different section form formulas are not uniform, and the methods cannot be simultaneously suitable for calculating the bending bearing capacity at normal temperature and high temperature.
Disclosure of Invention
The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for calculating a bending bearing capacity (i.e., an eccentric bearing capacity) of a concrete filled steel tube member unified at normal temperature and high temperature, which can easily and directly determine the bending bearing capacity of the concrete filled steel tube member in various cross-sectional forms under the actions of normal temperature and high temperature of a fire. In order to achieve the purpose, the invention adopts the following scheme:
the invention provides a method for calculating the bending bearing capacity of a concrete filled steel tube member unified at normal and high temperature, which is characterized by comprising the following steps of:
step 1, collecting relevant parameters of a concrete filled steel tube member
Collecting the yield strength, the elastic modulus and the concrete compressive strength of steel in the steel tube concrete member; collecting the length of a steel pipe concrete member, the cross section area of a steel pipe, the cross section area and the hollow rate of concrete; collecting the fire time of the steel pipe concrete;
step 2, respectively obtaining the average temperature of the steel pipe and the average temperature of the concrete according to the fire time; considering the fire time as zero under the condition of normal temperature;
step 3, determining the bending bearing capacity design value M of the steel pipe concrete member at normal temperature or high temperature by adopting the disclosed technical means according to the average temperature of the steel pipe and the concreteu,TStability factor of
Figure GDA0002319207820000023
Design value N of bearing capacity of axial compression strength0,TDesign value N of axial tension bearing capacity0t,TEuler critical force Ncr,T；
Step 4, calculating the bending bearing capacity of the concrete-filled steel tube component at normal temperature or fire high temperature:
Figure GDA0002319207820000021
m, N are respectively designed values of bending moment and axial force acting on the component;
Mu,Tthe design value of the flexural bearing capacity of the steel pipe concrete member at normal temperature or fire high temperature is obtained;
Figure GDA0002319207820000022
the stability coefficient of the steel pipe concrete member at normal temperature or fire high temperature;
N0,Tthe design value of the axial pressure strength bearing capacity of the steel pipe concrete member at normal temperature or fire high temperature is obtained;
N0t,Tthe design value of the axial tension bearing capacity of the steel tube concrete member at normal temperature or fire high temperature is obtained;
Ncr,Tthe Euler critical force of the steel tube concrete member at normal temperature or fire high temperature;
βmis the equivalent bending moment coefficient.
Further, the method for calculating the bending bearing capacity of the steel pipe concrete member unified at normal and high temperature provided by the invention can also comprise the following characteristics: in step 2, the average temperature of the steel pipe is calculated according to the following formula II, and the average temperature of the concrete is calculated according to the following formula III:
Figure GDA0002319207820000031
Figure GDA0002319207820000032
in the formula, Ts，
Figure GDA0002319207820000033
The average temperature (DEG C) of the steel pipe and the concrete under fire respectively;
T0the temperature is room temperature and is taken as 20 ℃;
ηsthe temperature change coefficient of the steel pipe under fire disaster;
θfis the fire temperature (. degree. C.), thetaf345log (480t +1), t being the duration of the fire (h);
m and n are concrete type correlation coefficients, and for siliceous aggregate concrete, m is 1, and n is 1; for calcareous aggregate concrete, m is 1.1, and n is 0.9; for lightweight aggregate concrete, m is 1.2, n is 1.2; for ordinary concrete, m is 0.94 and n is 0.78;
d is the equivalent thickness (m) of the steel tube,
Figure GDA0002319207820000034
As，Ac，Akcross-sectional areas (m) of the steel pipe, concrete and hollow portion, respectively2)；
Figure GDA0002319207820000041
The temperature change coefficient of the concrete section under fire disaster;
a. b is the hollow radius and the outer radius (m) of the concrete respectively;
psi is hollow rate, psi ═ Ak/(Ac+Ak)。
Further, the method for calculating the bending bearing capacity of the steel pipe concrete member unified at normal and high temperature provided by the invention can also comprise the following characteristics: the concrete-filled steel tube member is any one of a solid circular concrete-filled steel tube member, a solid polygonal concrete-filled steel tube member, a hollow circular concrete-filled steel tube member, and a hollow polygonal concrete-filled steel tube member. For example, the concrete-filled steel tube member may be a solid circular concrete-filled steel tube member, a solid polygonal concrete-filled steel tube member, a hollow circular concrete-filled steel tube member, a hollow polygonal concrete-filled steel tube member as shown in fig. 1. The polygonal concrete-filled steel tube member can be a square concrete-filled steel tube member, an octagonal concrete-filled steel tube member and the like.
Further, the method for calculating the bending bearing capacity of the steel pipe concrete member unified at normal and high temperature provided by the invention can also comprise the following characteristics: in step 4, under the condition of not considering the influence of the slenderness ratio of the member, calculating the bending bearing capacity of the concrete-filled steel tube member at normal temperature or high temperature of fire by adopting the following formula IV:
Figure GDA0002319207820000042
the normal and high temperature unified steel pipe concrete bending bearing capacity calculation and design formula and the source basis thereof are as follows:
the strength bending correlation curve of the concrete filled steel tube section at normal temperature can be obtained based on a plasticity limit analysis method (figure 2). According to the curve shape of the strength press bending correlation curve at normal temperature and the positions of a plurality of special points (respectively corresponding to the stress states of axial compression, pure bending and axial tension) on the curve, the steel pipe concrete strength press bending correlation equation at normal temperature is constructed and provided and is unified as a formula A:
Figure GDA0002319207820000051
m, N-design values for bending moment and axial force acting on the component, respectively;
Mu-design value of bending bearing capacity of steel pipe concrete at normal temperature;
N0-design value of strength bearing capacity of the steel pipe concrete at normal temperature;
N0tand the design value of the bearing capacity of the steel pipe concrete under normal temperature.
The formula A does not need sectional calculation, has simple form and convenient application, but is not suitable for calculating the bearing capacity of the concrete filled steel tube long column. In order to expand the applicability of the formula, the formula A is deduced and simplified by considering the second-order effect of the stress of the component, and a unified bending related equation of the concrete filled steel tube under the normal temperature, which is considered to be influenced by the slenderness ratio of the component, is provided as a formula B:
Figure GDA0002319207820000052
in the formula, βm-equivalent bending moment coefficient;
m, N-design values for bending moment and axial force acting on the component, respectively;
Mu-design value of bending bearing capacity of steel pipe concrete at normal temperature;
Figure GDA0002319207820000053
-stability factor of the steel pipe concrete at normal temperature;
N0-design value of strength bearing capacity of the steel pipe concrete at normal temperature;
N0t-design value of bearing capacity of steel pipe concrete under normal temperature;
Ncr-Euler critical force of concrete filled steel tube at normal temperature.
In order to verify the accuracy of the formula B, the concrete filled steel tube bending related curve determined by the formula B at normal temperature is compared with the calculation curves of formulas and finite element calculation results provided by other scholars, as shown in FIG. 3; the comparison of the calculated results of formula B with the experimental results is shown in fig. 4. The results show that the calculation precision of the formula B is high, the formula B adopts a form of multiplication, the form is very simple, excessive coefficients are avoided being introduced, the application range is wide, and engineering designers can conveniently select various concrete-filled steel tube members and carry out theoretical design.
For the calculation of the bearing capacity at high temperature of the fire, a steel pipe concrete section fire-resistant calculation model (figure 5) is established by adopting a plasticity limit analysis method, and a strength bending correlation curve (figure 6) of the steel pipe concrete section at high temperature of the fire is obtained. According to the characteristics of the curve, on the basis of the formula A, the concrete-filled steel tube strength bending related equations at normal temperature and high temperature of fire are provided and unified into the formula IV.
When the fire is in the zero moment, namely in the normal temperature state, the formula IV naturally degenerates into the formula A. The formula IV not only contains the advantages of the formula A, but also well embodies the continuity of the working performance of the concrete filled steel tube, and has stronger applicability.
The inventor researches a calculation method of bearing capacity of concrete filled steel tube under single stress states of axial compression and pure bending at normal temperature and high temperature of fire, and research results show that: the high-temperature bearing capacity calculation of the steel pipe concrete member which can bear the axial pressure load and the pure bending load at high temperature can be directly applied to a calculation formula at normal temperature, and only the material strength value and the elastic modulus value in the formula need to be replaced by corresponding values calculated by adopting an average temperature method. Similarly, under the combined action of the axial force and the bending moment load, the unified bending correlation equation B of the concrete-filled steel tube at normal temperature can be directly expanded to the high temperature of the fire based on the average temperature method. Finally, a normal-high temperature unified steel pipe concrete bending related equation is provided as the formula I.
Formula I adopts a form of multiplication, and normal temperature is a special case of fire zero time. Moreover, formula I can degrade to formula IV when the component slenderness ratio effect is not considered. The formula I is verified by using the existing relevant test data, and the comparison between the calculation result of the formula I and the test result is shown in FIG. 7. The result proves that the formula I has better applicability, simple formula form and is convenient for engineering designers to design at normal temperature and fire at high temperature.
For parameter M in the above formulau,T、
Figure GDA0002319207820000071
N0,T、N0t,TAnd Ncr,Tβ can be determined by the disclosed technical meansmThe value of (A) can refer to the relevant specification of the concrete filled steel tube.
Calculating the design value M of the flexural bearing capacity of the concrete filled steel tube at normal temperature and high temperatureu,TStability factor of
Figure GDA0002319207820000072
Design value N of bearing capacity of axial compression strength0,TDesign value N of axial tension bearing capacity0t,TEuler critical force Ncr,TThe equivalent strength and elastic modulus of the steel pipe and the concrete were calculated using the respective average temperatures. It is proposed that the average temperature of the steel tube and the concrete is calculated in the form of a multiplication, wherein the average temperature of the steel tube is calculated according to formula II and the average temperature of the concrete is calculated according to formula III, and the influence of different material types can be taken into account. The pair of the component temperature field calculation formula and the finite element calculation result in formula II, formula III and technical Specification for Steel pipe concrete Structure GB 50936 is shown in FIGS. 8 and 9. The comparison result shows that the temperature calculation formulas II and III provided by the invention are more accurate, the formula forms are simpler, and the application range is wider.
Action and Effect of the invention
1. The invention provides a method for calculating the bending bearing capacity of a concrete filled steel tube member, which can be simultaneously suitable for normal temperature and fire high temperature.
2. The method for calculating the bending bearing capacity is wide in application range, and not only is suitable for normal temperature and high temperature, but also is suitable for various member section forms.
3. The average temperature calculation method provided by the method is simple in form and accurate in calculation, and influences of different material types can be considered.
4. The method can simply, conveniently and directly determine the bending bearing capacity of the steel pipe concrete in various cross-section forms at normal temperature and high temperature of fire, and is favorable for promoting the application and popularization of the steel pipe concrete.
5. The method can be used for calculating the bending bearing capacity of the concrete-filled steel tube member in the building structures such as bridges, high-rise buildings, super high-rise buildings and the like at normal temperature and high temperature of fire, and has strong applicability.
Drawings
FIG. 1 is a cross-sectional view of a concrete filled steel tube member according to the present invention;
FIG. 2 is a typical strength bending correlation curve diagram of the concrete filled steel tube section at normal temperature;
FIG. 3 is a comparison graph of a press bending curve calculated by a unified formula at normal temperature and other research curves;
FIG. 4 is a graph comparing the results of the unified formula calculation with the test results at room temperature according to the present invention;
FIG. 5 is a schematic view of a concrete filled steel tube buckling calculation model under fire according to the present invention;
FIG. 6 is a graph of normalized typical buckling of concrete filled steel tubes according to the present invention, wherein (a) is solid concrete filled steel tubes and (b) is hollow concrete filled steel tubes, and each curve is sequentially increased in time by 30 minutes in the direction of the arrow;
FIG. 7 is a graph comparing the results of the unified formula calculation with the test results at high temperature of fire according to the present invention;
FIG. 8 is a comparison of the calculation formula of the average temperature of the steel pipe of the present invention with the normalized formula and finite element results, wherein (a) is the calculation of the normalized formula and (b) is the calculation of the formula of the present invention;
FIG. 9 is a graph comparing the calculation formula of the concrete average temperature of the present invention with the normative formula and finite element results, wherein (a) is the calculation of the normative formula of the prior art, and (b) is the calculation of the formula of the present invention;
Detailed Description
The concrete pipe member bending load-bearing capacity calculation method according to the present invention will be described in detail below.
< example one > Normal temperature calculation
When the bearing axial force and the bending moment act together at normal temperature, the unified bending related equation adopted by the calculation and design of the bending bearing capacity of the component is a formula I:
Figure GDA0002319207820000081
at normal temperature, calculating according to the fire occurrence time t as 0, wherein each parameter in the formula is calculated by adopting the following formula:
Figure GDA0002319207820000091
Figure GDA0002319207820000092
Figure GDA0002319207820000093
Figure GDA0002319207820000094
in the formula βm-equivalent bending moment coefficient, value reference concrete-filled steel tube relevant specifications;
n-design value of axial force acting on the member (N);
m is a design value of bending moment acting on the component (N mm);
Mu-design value of bearing capacity (N.mm) of steel pipe concrete under normal temperature;
ξ hoop coefficient of concrete-filled steel tube, ξ ═ Asfy/Acfck；
Figure GDA0002319207820000095
-the equivalent radius (mm) of the section of the concrete filled steel tube,
Figure GDA0002319207820000096
fy，fckrespectively at room temperatureThe lower design value (MPa) of the strength of steel and concrete;
As，Ac，Akcross-sectional areas (mm) of the steel pipe, concrete and hollow part, respectively2)；
Figure GDA0002319207820000097
-uniform stability factor of the steel pipe concrete at normal temperature;
Figure GDA0002319207820000098
the regular slenderness ratio of the steel tube concrete,
Figure GDA0002319207820000099
L0-the calculated length of the member (mm);
EscIsccombined bending stiffness (N mm) of concrete filled steel tube at normal temperature2)，
EscIsc＝EcIc+EsIs；
Es，EcModulus of elasticity (N/mm) for Steel and concrete, respectively2)；
Is，IcThe section moments of inertia (mm) of steel and concrete, respectively4)；
K-equivalent initial bending coefficient, K is 0.25-0.09Ke；
ke-equivalent constraint influence coefficient, ke＝(1-ψ)(n2-4)/(n2+20), n is the number of edges;
psi-hollow ratio, psi ═ Ak/(Ac+Ak)；
N0-design value of strength bearing capacity (N) of concrete filled steel tube at normal temperature;
N0tdesign value of axial tensile bearing capacity (N), N of concrete filled steel tube at normal temperature0t＝Asfy；
NcrEuler critical force (N) of concrete filled steel tubes at normal temperature.
< example two > calculation of fire at high temperature
When the axial force and the bending moment are applied together under the high temperature of a fire disaster, the unified bending related equation adopted by the calculation and the design of the bending bearing capacity of the component is a formula I:
Figure GDA0002319207820000101
first, the average temperatures of the steel pipe and the concrete are calculated using the following formulas II and III, respectively.
Figure GDA0002319207820000102
Figure GDA0002319207820000103
In the formula, Ts，
Figure GDA0002319207820000104
-the average temperature (deg.C) of the steel pipe and the concrete under fire respectively;
T0-room temperature, taken at 20 ℃;
ηs-the coefficient of variation of the temperature of the steel pipe in a fire;
θftemperature of fire (. degree. C.), θf345log (480t +1), t being the duration of the fire (h);
m and n are concrete type correlation coefficients, and for siliceous aggregate concrete, m is 1, and n is 1; for calcareous aggregate concrete, m is 1.1, and n is 0.9; for lightweight aggregate concrete, m is 1.2, n is 1.2; for ordinary concrete, m is 0.94 and n is 0.78;
d-the equivalent thickness (m) of the steel tube,
Figure GDA0002319207820000111
As，Ac，Akcross-sectional areas (m) of the steel pipe, concrete and hollow part, respectively2)；
Figure GDA0002319207820000112
-temperature coefficient of variation of the concrete section in fire;
a. b-the hollow radius and the outer radius (m) of the concrete, respectively;
psi-hollow ratio, psi ═ Ak/(Ac+Ak)。
Then, on the basis of the section temperature calculation, the following formula is adopted to calculate other parameters in the formula I:
Figure GDA0002319207820000113
Figure GDA0002319207820000114
Figure GDA0002319207820000115
Figure GDA0002319207820000116
Figure GDA0002319207820000117
Figure GDA0002319207820000118
Figure GDA0002319207820000119
Figure GDA00023192078200001110
Figure GDA00023192078200001111
Figure GDA00023192078200001112
Figure GDA00023192078200001113
in the formula βm-equivalent bending moment coefficient, value reference concrete-filled steel tube relevant specifications;
n-design value of axial force acting on the member (N);
m is a design value of bending moment acting on the component (N mm);
Mu,T-design value of flexural bearing capacity (N · mm) of concrete filled steel tube under fire;
ξT-hoop coefficient of concrete filled steel tube in fire;
Figure GDA0002319207820000121
-the equivalent radius (mm) of the section of the concrete filled steel tube,
Figure GDA0002319207820000122
Figure GDA0002319207820000123
-design values (MPa) for the strength of steel and concrete in fire, respectively;
As，Ac，Akcross-sectional areas (mm) of the steel pipe, concrete and hollow part, respectively2)；
Figure GDA0002319207820000124
Respectively representing the strength reduction coefficient of steel and the equivalent strength reduction coefficient of concrete under fire;
Figure GDA0002319207820000125
-uniform stability factor of concrete filled steel tube in fire;
Figure GDA0002319207820000126
the regular slenderness ratio of the concrete filled steel tube under fire,
Figure GDA0002319207820000127
L0-the calculated length of the member (mm);
(EI)sc,Tcombined bending stiffness (N.mm) of concrete-filled steel tubes in fire2)，
Figure GDA0002319207820000128
Figure GDA0002319207820000129
The modulus of elasticity (N/mm) of the concrete and of the steel respectively in case of fire2)；
Is，IcThe section moments of inertia (mm) of steel and concrete, respectively4)；
K-equivalent initial bending coefficient, K is 0.25-0.09Ke；
ke-equivalent constraint influence coefficient, ke＝(1-ψ)(n2-4)/(n2+20), n is the number of edges;
N0,T-design value of strength bearing capacity (N) of concrete filled steel tube in fire;
N0t,T-design value (N) of bearing capacity of steel pipe concrete under fire,
Figure GDA00023192078200001210
Ncr,T-euler critical force (N) of concrete filled steel tubes in fire.
The above embodiments are merely illustrative of the technical solutions of the present invention. The method for calculating the bending bearing capacity of the concrete filled steel tube member unified at the normal and high temperature according to the present invention is not limited to the contents described in the above embodiments, but is subject to the scope defined by the claims. Any modification or supplement or equivalent replacement made by a person skilled in the art on the basis of this embodiment is within the scope of the invention as claimed in the claims.

Claims (4)

1. A method for calculating the bending bearing capacity of a steel pipe concrete member unified at normal and high temperature is characterized by comprising the following steps:
step 1, collecting relevant parameters of a concrete filled steel tube member,
collecting the yield strength, the elastic modulus and the concrete compressive strength of steel in the steel tube concrete member; collecting the length of a steel pipe concrete member, the cross section area of a steel pipe, the cross section area and the hollow rate of concrete; collecting the fire time of the steel pipe concrete;
step 2, respectively obtaining the average temperature of the steel pipe and the average temperature of the concrete according to the fire time;
step 3, determining the design value M of the flexural bearing capacity of the steel pipe concrete member at normal temperature or high temperature according to the average temperature of the steel pipe and the concreteu,TStability factor of
Figure FDA0002319207810000011
Design value N of bearing capacity of axial compression strength0,TDesign value N of axial tension bearing capacity0t,TEuler critical force Ncr,T；
Step 4, calculating the bending bearing capacity of the concrete-filled steel tube component at normal temperature or fire high temperature:
Figure FDA0002319207810000012
m, N are respectively designed values of bending moment and axial force acting on the component;
Mu,Tthe design value of the flexural bearing capacity of the steel pipe concrete member at normal temperature or fire high temperature is obtained;
Figure FDA0002319207810000013
the stability coefficient of the steel pipe concrete member at normal temperature or fire high temperature;
N0,Tthe design value of the axial pressure strength bearing capacity of the steel pipe concrete member at normal temperature or fire high temperature is obtained;
N0t,Tthe design value of the axial tension bearing capacity of the steel tube concrete member at normal temperature or fire high temperature is obtained;
Ncr,Tthe Euler critical force of the steel tube concrete member at normal temperature or fire high temperature;
βmis the equivalent bending moment coefficient.
2. The calculation method for the bending bearing capacity of the constant-high temperature unified concrete filled steel tube component according to claim 1, characterized in that:
in step 2, the average temperature of the steel pipe is calculated according to the following formula II, and the average temperature of the concrete is calculated according to the following formula III:
Figure FDA0002319207810000021
Figure FDA0002319207810000022
in the formula, Ts，
Figure FDA0002319207810000023
The average temperature of the steel pipe and the concrete under fire respectively;
T0is at room temperature;
ηsthe temperature change coefficient of the steel pipe under fire disaster;
θfis the temperature of the fire, thetaf345log (480t +1), t being the duration of the fire;
m and n are concrete type correlation coefficients, and for siliceous aggregate concrete, m is 1, and n is 1; for calcareous aggregate concrete, m is 1.1, and n is 0.9; for lightweight aggregate concrete, m is 1.2, n is 1.2; for ordinary concrete, m is 0.94 and n is 0.78;
d is the equivalent thickness of the steel tube,
Figure FDA0002319207810000024
As，Ac，Akthe cross-sectional areas of the steel pipe, the concrete and the hollow part respectively;
Figure FDA0002319207810000025
the temperature change coefficient of the concrete section under fire disaster;
a. b is the hollow radius and the outer radius of the concrete respectively;
psi is hollow rate, psi ═ Ak/(Ac+Ak)。
3. The calculation method for the bending bearing capacity of the constant-high temperature unified concrete filled steel tube component according to claim 1, characterized in that:
the concrete-filled steel tube member is any one of a solid circular concrete-filled steel tube member, a solid polygonal concrete-filled steel tube member, a hollow circular concrete-filled steel tube member and a hollow polygonal concrete-filled steel tube member.
4. The calculation method for the bending bearing capacity of the constant-high temperature unified concrete filled steel tube component according to claim 1, characterized in that:
in step 4, under the condition that the influence of the slenderness ratio of the member is not considered, the following formula IV is adopted to calculate the bending bearing capacity of the concrete-filled steel tube member at normal temperature or high temperature of fire:
Figure FDA0002319207810000031
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CN110795879B (en) * 2019-10-29 2023-04-18 广西路桥工程集团有限公司 Method for calculating continuous bending bearing capacity of concrete filled steel tube member
CN111062164A (en) * 2019-12-13 2020-04-24 桂林理工大学 High-temperature-resistant design method for coal gangue-based geopolymer concrete beam
CN112231862B (en) * 2020-10-20 2024-02-20 杭州铁木辛柯建筑结构设计事务所有限公司 Rectangular steel tube concrete column section limit bearing judgment method under composite stress state
CN112307412B (en) * 2020-11-03 2024-03-12 杭州铁木辛柯建筑结构设计事务所有限公司 Method for judging ultimate bearing of wide concrete filled steel tube weak shaft under composite stress state

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102912936A (en) * 2012-10-16 2013-02-06 浙江树人大学 Method for designing FRP (fiber reinforce plastic) tube-concrete-steel tube combined column
CN104679950A (en) * 2015-02-09 2015-06-03 查晓雄 Bearing capacity calculation and designing method for concrete-filled steel tube member with internal stiffeners
JP6166574B2 (en) * 2013-04-04 2017-07-19 株式会社竹中工務店 Building design method

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR101315692B1 (en) * 2011-09-29 2013-10-10 한국전력공사 Prestress force assessment methodology of bonded tendon using stress wave velocity by impact

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102912936A (en) * 2012-10-16 2013-02-06 浙江树人大学 Method for designing FRP (fiber reinforce plastic) tube-concrete-steel tube combined column
JP6166574B2 (en) * 2013-04-04 2017-07-19 株式会社竹中工務店 Building design method
CN104679950A (en) * 2015-02-09 2015-06-03 查晓雄 Bearing capacity calculation and designing method for concrete-filled steel tube member with internal stiffeners

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
多层套箍钢管混凝土构件在不同温度下承载力的研究;万城勇;《中国博士学位论文全文数据库 工程科技II辑》;中国学术期刊（光盘版）电子杂志社;20180115(第1期);第140-158页 *
钢管混凝土构件轴压承载力设计公式的可靠度分析;余敏 等;《建筑钢结构进展》;20170324;第19卷(第2期);第45-52页 *

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