KR100499839B1 - incremental launching method for bridge construction by the lifting and dropping the support point of the nose - Google Patents

Abstract

The present invention relates to an ILM bridge construction method using a point elevating action. In order to improve the durability of the bridge structure by reducing the maximum size of the parent moment generated during the bridge construction step, the tip of the propulsion nose, which is the tip of the bridge, has the maximum bending part moment. In the process of raising the propulsion nose point by using lifting equipment when reaching the pier formed in front, the weight and cross-sectional characteristic value of the bridge upper structure, the propulsion nose weight and cross-sectional characteristic value, the span length of the bridge upper structure, and the propulsion In the hypothesis consisting of the nose length and the position of the connection between the bridge top structure and the propelling nose in the span that induces the maximum parent moment, the size and timing of the point lift are determined by the function of the maximum parent moment function and the point rise size function. Distribution of flexural moments less than or equal to the maximum flexural moment size to be reduced in In the hypothesis step showing the point elevating action by repeatedly acting every bridge piling, to reduce the specific weight of the upper structure of the bridge and the weight of the reinforcement of the inside, and to make the length of the bridge upper structure long span, economical and forming Excellent bridge construction can be achieved.

Description

Incremental launching method for bridge construction by the lifting and dropping the support point of the nose}

The present invention relates to an ILM bridge construction method using a point elevating action. More specifically, in the extrusion bridge construction, which is constructed by the ILM (Incremental Lauching Method) bridge construction method using a propulsion nose that is widely used in the construction of various road bridges and railway bridges, the upper part of the bridge at a specific point in time when the upper part of the bridge is extruded The present invention relates to an extruded bridge construction method that can increase the durability of the entire bridge and reduce the use of bridge equipment by proposing a more reasonable extruded bridge construction method using an apparatus that can cause the rise and fall of the artificially.

Conventional ILM bridge construction method uses a type I girder as a propulsion nose, but the length of the propulsion nose is 60 ~ 70% of the maximum span length of the bridge, and the rigidity (the bridge upper structure and propulsion by the arithmetic mean in the span) Rigid ratio of nose and weight are produced by about 1/10 of the upper structure of bridge, and the hypothesis of ILM bridge is various shapes made of the upper structure of concrete (concrete or steel, etc.) Girders) can be manufactured continuously, and the propulsion nose is installed using an apparatus for extruding the bridge upper structure located in the alternating state, that is, a vertical or horizontal jack, with the propulsion nose installed on the front of the first bridge upper structure. At the same time, the building of the alternating rear is additionally provided so that it can be installed continuously with the first bridge superstructure extruded. It is a method to finally complete the bridge by repeating the steps of manufacturing and installing the bridge superstructure.

In the conventional ILM bridge construction method, the design and construction of the upper structure of the bridge, as shown in Figure 1a and 1b, before the extrusion step of the bridge upper structure 300, the propulsion nose is formed (propulsion nose passing through the bridge C and After the passage), the stability and durability of the bridge during the construction can be said to be determined by the magnitude of the maximum bending parent (MB) size generated in the bridge B (100).

Looking in more detail, the conventional ILM bridge construction method maintains the rigidity (weight) of the propelled nose to less than 1/10 of the rigidity (weight) of the bridge upper structure, as shown in Figure 1a, passing through the bridge C (200) As shown in FIG. 1B, the bridge upper structure 300 in which the propelling nose is installed is the bending parent in the cantilever state based on the bridge B, and the bending parent generated after the tip of the propelling nose 400 reaches the bridge C 200. Design and construction are based on the condition that the cement has a larger value. The reason is that the bending parent of the bridge B (100) generated by increasing the rigidity (weight) of the propelling nose to 1/10 or more of the rigidity (weight) of the bridge upper structure in the cantilever structure system in the extrusion step as shown in FIG. This is because the size is much larger than the bending non-cement size of the pier B 100 in the continuous beam structure system of FIG. In other words, rather than increasing the rigidity (weight) of the propelled nose to 1/10 or more of the rigidity (weight) of the bridge upper structure, the rigidity (weight) of the propelled nose is less than 1/10 of the rigidity (weight) of the bridge upper structure. This results in a smaller bending parent moment on the bridge superstructure with respect to bridge B. In this state, the bending parent moment of bridge B in the extrusion step of the bridge upper structure as shown in FIG. As a result, the ILM bridge construction method maintains the stiffness (weight) of the propulsion nose at 1/10 or less of the stiffness (weight) of the bridge superstructure, and the pier C ILM Bridge is designed and constructed on the basis of the bending moment which occurs when the tip of the propulsion nose of the bridge upper structure with the propulsion nose passing through reaches the pier C.

In the conventional method of constructing an ILM bridge, as shown in FIG. 1B, the maximum bending parent size is excessively 1.45 to 1.60 times larger than that of a general pier of a conventional continuous beam structure system, and thus, the extrusion process is performed like the ILM bridge construction method. This reduces the durability of the bridge upper structure (box-shaped concrete or steel girders, etc.), and has a problem that the construction cost increases due to the increase in the amount of material required.

Accordingly, in the bridge construction extruded like the ILM bridge construction method, as shown in Figure 1b, a method of reducing the maximum bending moment of the bridge B can not but be proposed in various ways, in particular the prior art related to the present invention This relates to a replacement compression bridge construction method (hereinafter referred to as prior art) disclosed in Japanese Patent Laid-Open No. 53-111757.

That is, in the prior art, as shown in Fig. 1c, two means are largely proposed to reduce the maximum bending moment in the bridge B. This means extrudes the bridge upper structure with a propelled nose as shown in FIG. 1A, but at the position before the maximum bending moment at the bridge B, which is calculated beforehand, before the tip of the propulsion nose reaches the bridge C Raise the propulsion nose of the upper structure of the bridge by using the jack installed on the upper surface of C, and place the insert of concrete block or rubber plate between the lower surface of the propulsion nose and the upper part of the bridge C. Extrude the bridge structure. In other words, artificially, the maximum bending parent moment generated in the bridge B is reduced by lifting the upper bridge structure in which the propulsion nose is installed. Furthermore, when the propulsion nose is out of the position to generate the maximum bending parent moment, the jack is lifted again to remove the insert, and this operation is repeated each time for each pier to finally construct the bridge.

However, these prior arts have a number of technical problems. First, the structural system of the bridge bridge is in a state in which the bending of the maximum parent moment and the maximum moment is alternately received. In other words, the section design and stability review of the upper part of the bridge should be conducted together with the maximum parent moment and the constant moment, but the maximum bending parent moment in the bridge B is larger than the flexural constant moment in any other part. Of course, the technical idea of simply lifting the upper bridge structure with a propelled nose without any technical limitations is to lift the upper bridge structure, which is not limited to the bending moment that may be larger than the maximum secondary bending moment of bridge B. The safety of the bridge must be reviewed. If the bending constant moment occurring in the bridge upper structure by simply lifting the bridge upper structure with a propulsion nose is larger than the maximum bending parent moment in bridge B of Fig. 1b, which is generally accepted, this prior art has no technical value. Because it can disappear. This is a problem that can be similarly applied when lowering a bridge upper structure in which a propulsion nose is installed.

As a result, the prior art can verify the economic effect of reducing the maximum parental force while verifying the structural stability based on the dynamic logic for each bridge having different design conditions without the size of the bridge structure being determined. It should be expected, however, that the prior art has no dynamic basis for the technical idea of lifting the bridge tip (propulsion nose), especially for descending points "after passing the position of the maximum parental moment". However, this is the result that the propensity to change the maximum parental size for the hypothesis step is not properly reflected.

That is, as shown in FIG. 6, the maximum parental size according to the construction stage of the ILM bridge shows a change in the parabolic shape with a very gentle slope, so even though the maximum parental moment has passed the vertex indicating the maximum parental force, Since there is no specific technical means for the time of the point drop, there is a dynamic contradiction in which the magnitude of the similar stress due to the minute difference of the parent moment is moved only to the location where the maximum stress does not change. It is analyzed that there is no construction case applied to date because of the problem of adverse effect that the durability quality of the superstructure decreases with the increase of the constant moment.

Therefore, the means for solving the structural problems of the prior art, that is, the upper portion of the bridge over which the propulsion nose is installed, how much to raise at any point during the construction stage, and further down at some point to design the conventional ILM bridge and Whether or not the size of the maximum bending parent moment in bridge B of Fig. 1b, which is accepted as the basis of construction, can be effectively reduced (regardless of the action and size of the bending constant moment acting on the upper structure of the bridge where the protruding nose is installed). There is an urgent need to develop specific technologies for verification by theoretical considerations and construction methods.

The present invention is to achieve the above technical problem,

An object of the present invention is to propose a method for determining the size and timing of the point rise that should occur in a specific pier by determining the reduction size for the maximum parent moment occurring in the hypothesis step that determines the behavior characteristics of the IEL bridge design and construction In addition, the point of descent can be determined to maintain the point rise to improve the durability of the upper structure due to the reduction of the maximum parent moment, while on the other hand, the increase of the constant moment does not cause a detrimental effect on the durability of the upper structure. By presenting the method together, the maximum parental reduction effect according to the series ILM bridge hypothesis is applied to the construction conditions of any bridge, so that durability is improved, economical, and long span can be achieved compared to conventional ILM bridge. It is to induce an equation and apply it to construction.

The present invention, in order to achieve the above technical problem, in particular in the extrusion bridge construction method, such as ILM bridge construction method, a phenomenon that appears repeatedly the same step until the completion of the construction of the bridge upper structure, the hypothesis as shown in Figure 1b An important technical means devised in the present invention in order to reduce the maximum bending parental force (MB) occurring in the step span L2 is to use a lifting device (hydraulic jack, etc.) to generate a point elevating action on a bridge upper structure in which a propelled nose is formed. The present invention provides a method for reducing the maximum bending parental moment occurring in a specific pier (pier B in FIG. 1b), and in particular, quantitatively obtaining the point lift timing and size. Including the verification by the structural analysis program experiments) Hereinafter, the most preferred embodiment of the present invention will be described in detail with reference to FIGS. The people.

In the ELM bridge construction method using the point elevating action of the present invention, after the alternating and pier construction, the extrusion construction step of the bridge upper structure 300 is repeated and finally completed in the ILM bridge construction, the repeated extrusion In the construction stage, the bridge tip portion of the bridge top structure 300 and the propelling nose 400 at the point of the bridge 2 (200) located in front of the bridge 1 (100) where the maximum bending parent moment (MB) occurs ( Raising upwards vertically before the 500 reaches the position where the maximum bending parent moment value occurs (S200); And

And lowering the bridge tip portion raised in the step S200 vertically downward after reaching the position where the maximum bending parent moment value occurs between the bridge upper structure and the propulsion nose value (S300). In particular, the step S200 The rise of the bridge tip at

Based on the bridge 1 (100) where the maximum bending parent moment occurs, the bending parent moment diagram according to the distance axis (xL2) through which the connecting portion 500 of the upper bridge structure 300 and the propelling nose 400 passes (BMD, Determining a second parabolic diagram; After determining the bending parent moment (ΔMB) to be reduced, the value of the bending parent moment degree corresponding to the MB-ΔMB value obtained by subtracting the ΔMB value based on the maximum value MB of the bending parent moments (D1) (D2) and determining the position (L1, L2) of the distance axis corresponding thereto; Among the values of D1 and D2, before the connection portion 500 of the bridge upper structure 300 and the propelling nose 400 reaches the position where the maximum bending parent moment MB occurs, the corresponding D1 value is set as the threshold value 1. Determining; The position L1 of the distance axis corresponding to the threshold value 1 is determined, and the point of time when the bridge tip is raised is determined at least before the connection portion 500 of the bridge upper structure 300 and the propulsion nose 400 passes through the L1. Comprising;

The falling time of the bridge tip portion of the step S300,

Based on the bridge 1 (100) where the maximum bending parent moment occurs, the bending parent moment diagram according to the distance axis (xL2) through which the connecting portion 500 of the upper bridge structure 300 and the propelling nose 400 passes (BMD, Determining a second parabolic diagram; After determining the bending parent moment (ΔMB) to be reduced, the value of the bending parent moment degree corresponding to the MB-ΔMB value obtained by subtracting the ΔMB value based on the maximum value MB of the bending parent moments (D1) (D2) and determining the position (L1, L2) of the distance axis corresponding thereto; Among the D1 and D2 values, the corresponding D2 value after the connection portion 500 of the bridge upper structure 300 and the propelling nose 400 reaches the position where the maximum bending parent moment MB occurs is the threshold value 2). Determined by; The position L2 of the distance axis corresponding to the threshold value 2 is determined, and the point descent time of the bridge tip portion is determined before at least the connection portion 500 of the bridge upper structure 300 and the propulsion nose 400 passes through the L2. It comprises; a.

First, based on the structural dynamics, first, the formula for calculating the bending moment in bridge pier 1 (pier B in the case of FIG. 1b) where the maximum bending moment occurs in the ILM bridge construction step shown in FIG. In this way, a trend curve of the maximum bending parent moment (MB) in the pier 1 is derived. Furthermore, in order to reduce the maximum bending moment, when the bridge tip portion (propulsion nose) is raised from the bridge 2 (pier C in FIG. 1C) installed just in front of the bridge, the maximum bending parent moment is disclosed. As a result, when the maximum bending parent moment to be reduced is determined in advance, it is disclosed that according to the specifications of the bridge upper structure, the timing of elevating and rising the point at the bridge C can be determined.

Lastly, the method of obtaining the point elevating time of the bridge tip at the bridge C is discussed in detail.

Calculation formula of bending parent moment in pier 1 (pier B in FIG. 1b) where maximum bending parent moment occurs

① For the ILM temporary structure system shown in FIG. 1B, when the value of x (relative to the pier B) representing the state of movement of the connection portion of the bridge upper structure and the propulsion nose is (0.4, 0.6, 0.8) respectively, the pier B The equation for the bending parent moment can be found as follows.

As shown in Fig. 2, for the maximum parental hypothesis step of a general ILM bridge, assuming an equivalent structural system capable of theoretical solution (L1, L3 ≤ L2, which means the span between each pier). Weight (W1), bulkhead load (P), propulsion nose weight (W2) loaded in L2 span, propulsion nose weight (W3) loaded in L3 span, etc. It can be applied to any design depending on the design, so that the parent moment (MB) in the bridge B generated in the bridge B can be solved as a third-order cross-section indeterminate structural system, using the following equations (1), (2), ( Can be defined as 3).

(1) Bending parent moment at bridge B when the bridge top structure and propulsion nose connection is x = 0.4 L2

(2) Bending parent moment at bridge B when the bridge top structure and propulsion nose connection is x = 0.6 L2

(3) Bending parent moment at bridge B when the bridge top structure and propulsion nose connection is x = 0.8 L2

In formulas (1), (2) and (3), A1, A2, A3, B1, B2, and B3 are

As

In the case of A1, A2, and A3, respectively, in Fig. 3, the size of the bending moment corresponding to each hypothesis step x = (0.4, 0.6, 0.8) L2 occurring at the position of the connection portion between the bridge upper structure and the propulsion nose,

B1, B2, and B3 are the bending non-cement sizes corresponding to the respective hypothesis steps x = (0.4, 0.6, 0.8) L2 occurring in the piers C in FIG. 3, respectively.

<Trigger curve formula of maximum bending parent moment (MB) in pier 1>

In general, in view of the fact that the moment change generated during ILM bridge construction is shown as a secondary parabolic shape by the first fixed load, the change curve of the maximum bending parent moment (MB) generated in the bridge B in the present invention is described. Using the results of the three hypothesis steps (1) (2) (3) above, it is derived as a quadratic function as follows.

(4)

Thus, the maximum bending parental trend curve generated in the bridge B in the construction stage of the bridge bridge I, as shown in Figure 1b can be derived as shown in Equation (4), the overall shape of the curve in the form of a secondary parabola 3, 5 and 6 are the same.

In the case of Fig. 1B, the maximum bending parent moment decreases when the bridge tip is raised at the bridge C.

At the position of pier C 200 of the equivalent structural system shown in FIG. 2, the reduction moment ΔMB induced in pier B generated by acting as point rise Vc is as follows.

(5)

Here, E1I1 is the bending stiffness of the upper bridge structure, k is a dimensionless value as a ratio of the bending stiffness (E2I2) of the propulsion nose based on the bridge upper structure.

Thus, it can be seen that when the bridge tip is lifted at the bridge C, the difference value is proportional to the lifting size compared with the case where the bridge tip is not lifted at the bridge B, and this size is the maximum bending part moment according to Equation (4). It can be seen that the trend curve can be obtained by deriving it.

<How to find the point of time of the point rising and falling of the bridge tip at Pier C>

Since the problem of determining the point elevating time is a problem that involves the stability of a very important structure as described in the problems of the prior art when the construction of the ILM bridge by the elevating point, the problem of the present invention The technical idea is to elevate the point at the hypothesis stage that indicates the moment size less than or equal to the maximum bending parent (ΔMB) size to be reduced in each pier. This action can have stability of the structure because only the desired reduced parent size is maintained for any hypothesis step.

3 and 6, first, the horizontal axis represents the hypothesis step, and the origin of the coordinate axis is the bridge B, which indicates the position at which the connecting portion between the bridge upper structure and the propulsion nose moves on L2. When the transition curve representing the parent moment is shown along the horizontal axis according to Equation (4) above, the parabolic shape is formed as shown below in Fig. 3, and the position of the connecting portion between the bridge upper structure and the propulsion nose is specified on the horizontal axis in the span L2. It can be seen that the maximum bending buoyant value at Pier B when changing to the position (described as xL2), and that the peak H1 of the maximum bending parent men can be formed at approximately x = 0.6 L2. Can be. At this time, in consideration of the ΔMB to be reduced in advance (usually, about 10% of the maximum bending parent moment in the pier B is reduced) (of course, it can be more than that). Subtracted, MB- DELTA MB (D3) can be obtained from FIG. The MB-ΔMB value can be obtained from Equation (6) below.

(6)

In FIG. 6, the left point is referred to as the threshold value 1 (D1) and the right value is referred to as the threshold value 2 (D2). Obtaining the threshold 1 and the threshold 2 is to find a hypothesis step that shows the moment size equal to or less than the same value based on the maximum bending parent moment ΔMB to be described above.

The threshold value 1 and the threshold value 2 mean rising time and falling time of the bridge tip portion in the present invention, respectively. In other words, if the bridge tip portion is lifted by Vc in bridge C by Eq. (5) to reduce the maximum bending parent moment in bridge B, the maximum bending parent moment as much as △ MB is reduced. The bridge is extruded to produce the maximum bending moment by MB. As a result, the ascending time at bridge C at the bridge tip meets the horizontal axis at threshold 1, which will be the time when the connection between the bridge upper structure and the propulsion nose passes through the bridge B at roughly x = 0.45L2. However, lifting the bridge tip requires uptime of the lifting equipment, so the bridge tip must actually be lifted before threshold 1. At this time, the lifting time in advance may be determined in consideration of the performance of the lifting equipment, construction errors, and the like. In other words, the threshold 1 is that the bridge tip portion should be raised by Vc at least at this point.

Similarly, the descent time at bridge C at the bridge tip is the point D2 where it meets the horizontal axis at the threshold 2, and at least the descent time is at the rising time since the descent of the bridge tip must be completed before at least the threshold 2 is reached. Similarly, the lowering should be started in advance considering the capacity and construction error of the lifting equipment.

That is, in the present invention, the rise time and the fall time of the upper end of the bridge are determined by the threshold value 1 and the threshold value 2, and in the actual construction, the rise time and the fall time are determined according to the capacity of the lifting equipment and the degree of construction error.

In detail, examples of the rise and fall times of the upper end of the bridge, the maximum bending parent (△ MB) size to be reduced to 10% of the maximum bending parent men at the bridge B, quantitatively 700ton-m above formula ( According to 6), the elevating timing of the point can be obtained as follows.

In order to cause such a reduction moment magnitude, the point rising magnitude (Vc) is calculated from Equation 5 to 41 (mm), and the result of the moment reduction and the elevation time result are shown in Fig. 6 as shown in Fig. 6 and Threshold 1 and Threshold 2. When D1 and D2 are determined and the corresponding xL2 values are determined, at least the time corresponding to xL2 (L1) corresponding to the threshold 1, that is, before the connection between the bridge upper structure and the propulsion nose reaches D1. The upper end of the bridge shall be raised from the bridge C, and the upper end of the bridge shall be lowered from the bridge C before the time corresponding to xL2 (L2) corresponding to the threshold 2, that is, the connection between the bridge upper structure and the propulsion nose reaches D2.

<Comparison and review of theoretical and computational structural analysis results for "Yumokcheon Bridge in the East Sea-Jummunjin West Coast Highway Expansion Section between 1996" (Figure 5 is a cross-sectional view of the upper structure)

The structure to be reviewed was compared and analyzed the theoretical formula and computational structural analysis results for “Yonggok Cheonyo Bridge in the West Sea Highway Expansion Section between Donghae and Jumunjin in 1996” (Fig. 4 represents the cross section of the upper structure of the bridge and its specifications). Load size, cross-sectional characteristic value, size of propulsion nose weight, etc. of the upper structure of the bridge applied to the experiment as shown in Figure 4 are as follows.

A; The area of the bridge's upper structure is 8.9 m2

I1; Second moment of cross section of the bridge superstructure 10.66 m4

P; Bulkhead section load size at the connection of the bridge superstructure 47.5 ton

k; Relative flexural stiffness (E2I2) ratio of propelled nose located in L2 span based on flexural stiffness (E1I1) of bridge superstructure 0.115

E1; Modulus of elasticity of bridge superstructure t / m2

E2; Modulus of propulsion nose t / m2

w1; Unit weight of bridge superstructure 22.5 t / m

w2; Unit weight of propulsion nose located in L2 span 2.34 t / m

w3; Unit weight of propulsion nose over L2 span 1.25 t / m

Drawing up the maximum moment moment curve in the hypothesis step where the maximum bending parent moment occurs When the property values of the target structure shown in Fig. 4 are entered into equations (1), (2), and (3), pier B is as follows. Equation (6) is calculated.

Investigation of the size of the parent moment (MB) of the bridge B (100) between the proposed result of the present invention and the computational structural analysis experiment according to the distance change xL2 of the extrusion step Street MB error Theory Computational Structural Analysis 0.3L 4240.08 4160.02 1.9% 0.4L 5503.52 5503.94 0.0% 0.5L 6306.00 6409.45 1.6% 0.6L 6647.52 6660.53 0.2% 0.7L 6528.08 6430.54 1.5% 0.8L 5947.46 5990.13 0.7%

As shown in Table 1, the error of the results of the trend curve and the computational structural analysis experiment presented in the present invention is only 1.9%, it is judged that it can be effectively used in the actual ILM bridge construction. 1, Fig. 5)

The extrusion method using the rising and falling points greatly improves the durability of the structure by drastically reducing the maximum moments generated during the construction of the segment prestressed concrete and steel (STEEL) bridges for the ELM bridge. In addition, it reduces the height of ILM bridge and reduces all materials required for bridge construction such as concrete, prestressing steel, steel (STEEL), anchorage, rebar, longitudinal and transverse reinforcement. To produce the effect of. On the other hand, this ripple effect has a chain effect of reducing the number of installation and size of the supporting capacity, the pier and foundation of the substructure, and ultimately increase the durability of the superstructure during the construction of ILM bridge In addition, economical construction can be realized.

Fig. 1A is a state diagram of the construction stage before the tip of the bridge tip (propulsion nose) reaches the bridge C.

FIG. 1B is a state diagram showing the maximum deflection occurring in the span L2 and the maximum parental moment MB in the bridge B when the bridge tip C (propulsion nose) has reached the bridge C. FIG.

FIG. 1C is a state diagram showing a parent moment ΔMB that is reduced due to deflection and point rise that occurs when the point of the bridge tip (propulsion nose) is raised in the state of FIG. 1B.

FIG. 2 is a state diagram showing an equivalent structural system assumed for presenting a theoretical solution with respect to a hypothetical structural system in which a maximum parent moment occurs.

3 is a conceptual diagram of the moment size (ΔMB) and the point lowering action reduced by raising the propulsion nose point using the lifting equipment.

4 is a cross-sectional view of a bridge upper structure in which specifications for comparison between a result of a functional formula and a computational structural analysis are described.

FIG. 5 is a comparison result between the functional equation and the computational structural analysis experiments proposed in the present invention for the generation parent moment size of the bridge B according to the change of the L2 span hypothesis step of the ILM bridge.

Figure 6 is an envelope diagram showing the maximum reduction of the parent moment in the pier B, according to the point rise and fall theory of action proposed in the present invention.

<Description of the symbols for the main parts of the drawings>

100: pier B 200: pier C

300: bridge upper structure 400: propulsion nose

500: bridge top structure and propulsion nose connection 600: bridge A

x L: Length (m) indicating the construction stage where the tip of the bridge superstructure is in L2 span

MB: Moment at Pier B during extrusion in temporary construction system (t-m)

ΔMB: Reduced moment at piers B due to burial (t-m)

L1, L2: Bridge A, B span length of the upper structure of the bridge (m)

L3: Propulsion nose length (m)

Vc: magnitude causing point rise (m)

w1: Weight per unit length of the bridge superstructure (t / m)

w2: Weight per unit length of propulsion nose located in L2 span (t / m)

w3: Weight per unit length of bridge tip over bridge C (t / m)

x1: Fixed end indefinite bending moment occurring at Pier A in the equivalent structural system (t-m)

E1: modulus of elasticity of the bridge superstructure (t / m2)

I1: Second moment of cross section of bridge superstructure (m4)

E2: modulus of elasticity of propulsion nose at bridge tip (t / m2)

I2: Second moment of cross section of propulsion nose at bridge tip (m4)

P: Bulkhead load of the cross section of the tip of bridge superstructures loaded within L2 span (ton)

k: Flexural stiffness ratio of propulsion nose section based on flexural stiffness of bridge superstructure (dimensionless dimension)

Claims (3)

delete After constructing the alternating and pier, in the ILM bridge construction in which the extrusion construction step of the bridge upper structure is repeated and finally completed, the repeated extrusion step is based on the pier 1 where the maximum bending parent moment (MB) occurs. Step of raising the bridge tip portion vertically upwards before reaching the position where the maximum bending parent moment occurs at the bridge front portion at the point of bridge 2 located forward; And lowering the bridge tip portion lifted in the step S200 vertically downward after reaching the position where the maximum bending parent moment value occurs between the bridge upper structure and the propelling nose connection portion (S300). The rising point of the bridge tip portion of the step S200, the bending parent moment according to the distance axis (xL2) passing through the connecting portion of the bridge upper structure and the propulsion nose on the basis of the pier 1 where the maximum bending parent moment occurs Determining (BMD, secondary parabolic diagram); After determining the bending parent moment (ΔMB) to be reduced, the value of the bending parent moment degree corresponding to the MB-ΔMB value obtained by subtracting the ΔMB value based on the maximum value MB of the bending parent moments (D1) (D2) and determining the position (L1, L2) of the distance axis corresponding thereto; Setting the corresponding D1 value as a threshold value 1 before the connection portion of the bridge upper structure and the propelling nose reaches a position where the maximum bending parent moment MB occurs among the D1 and D2 values; Determining a position L1 of the distance axis corresponding to the threshold value 1, and determining a point in time at which the bridge tip (propulsion nose) rises at least before the connection between the bridge upper structure and the propulsion nose passes through the D1; ILM bridge construction method using a point elevating action, comprising a. The falling time point of the bridge tip portion of the step S300, Determining a bending parent moment diagram (B.M.D, secondary parabolic diagram) according to a distance axis (xL2) through which the connecting portion of the bridge upper structure and the propulsion nose passes based on the bridge 1 where the maximum bending parent moment occurs; After determining the bending parent moment (ΔMB) to be reduced, the value of the bending parent moment degree corresponding to the MB-ΔMB value obtained by subtracting the ΔMB value based on the maximum value MB of the bending parent moments (D1) (D2) and determining the position (L1, L2) of the distance axis corresponding thereto; Setting the corresponding D2 value as the threshold value 2 after the connection between the bridge upper structure and the propelling nose reaches a position where the maximum bending parent moment MB occurs among the D1 and D2 values; Determining a position L2 of the distance axis corresponding to the threshold value 2, and determining a time point for descending the bridge tip (propulsion nose) before at least the connection portion between the bridge upper structure and the propulsion nose passes through D2; ILM bridge construction method using a point elevating action comprising a.