CN106917419A - A kind of simplified analogy method of bridge great-leap-forward prestressing force cushion cap support - Google Patents

Abstract

A kind of simplified analogy method of bridge prestress cushion cap support, when the support of great-leap-forward foundation platform is simulated, two dimensional model, the every campshed of direction across bridge etc. is reduced on behalf of one by basis, and stake top is k by thrust stiffness_w1、k_w2、k_w3Three springs be connected with cushion cap bottom, to transmit horizontal force, vertical force and torsion；During calculating, soil rigidity coefficient gamma is solved using " m " method_cc、γ_aa、γ_ab、γ_ba、γ_bb、γ_bc、γ_cb, soil rigidity coefficient is finally imported into general bridge software for calculation, solve every mechanical index of cushion cap.The connection of stake and cushion cap is reduced to spring connection by the present invention, and can be on the premise of more accurate analog basis stress, applicability be stronger, computation model is relatively easy, will not produce relative effect to calculation scale, meets design requirement.Computational methods of the invention are based on current specifications, and result of calculation (i.e. soil rigidity coefficient) can be directly substituted into general Software for bridge analysis, for cushion cap checking computations.

Description

A kind of simplified analogy method of bridge great-leap-forward prestressing force cushion cap support

Technical field

The present invention relates to a kind of simplified analogy method of bridge great-leap-forward prestressing force cushion cap support.

Background technology

In modern city, the facility such as subway, Large Underground pipe and road tunnel occupies big portion Divide urban underground space.Thus, some bridge foundations are needed across these Large Underground barriers. To solve such problem, in Bridge Design, it is typically employed in cushion cap and applies prestressed side Method come improve basis span ability.For such prestressing force cushion cap support simulation, it is necessary to depth Enter research.

Traditional analogy method is soil spring model method, and stake is divided into mono- section of 3-5m's by the method Pile element, corresponding unit Pile side soil is reduced to soil spring, by soil to pile element non-uniform Distribution Elastic resistance is reduced to spring supporting.Although spring model has some advantages, but due to pile foundation Plinth modeling is extremely complex, and element number is numerous, and calculating speed is extremely slow, it is difficult to meet present engineering Design requirement.

The content of the invention

For above-mentioned some problems, the present invention proposes a kind of letter of bridge prestress cushion cap support Change analogy method, the analogy method is applied to cushion cap support in simulation great-leap-forward basis, with building The advantage that mould is simple, calculating speed is fast.

As above conceive, the technical scheme is that：A kind of letter of bridge prestress cushion cap support Change analogy method, it is characterised in that：

When the support of great-leap-forward foundation platform is simulated, basis is reduced to two dimensional model, direction across bridge On behalf of one, stake top is k by thrust stiffness to every campshed etc._w1、k_w2、k_w3Three springs with Cushion cap bottom connects, to transmit horizontal force, vertical force and torsion；During calculating, using " m " Method solves soil rigidity coefficient gamma_cc、γ_aa、γ_ab、γ_ba、γ_bb、γ_bc、γ_cb, wherein γ_ccTo hold Platform produces vertical unit displacement, the vertical counter-force sum in cushion cap bottom；γ_aaFor cushion cap produces level list Bit Shift, cushion cap bottom horizontal reacting force sum；γ_ab=γ_baFor cushion cap produces unit rotation, cushion cap bottom Horizontal reacting force or cushion cap produce horizontal unit displacement, cushion cap bottom recurvation square；γ_bbFor cushion cap is produced Unit rotation cushion cap bottom recurvation square；γ_bc=γ_cbCushion cap produces unit rotation, the vertical counter-force in cushion cap bottom Or cushion cap produces vertical unit displacement, cushion cap bottom recurvation square；Finally soil rigidity coefficient is imported General bridge software for calculation, solves every mechanical index of cushion cap.

The connection of stake and cushion cap is reduced to spring connection by the present invention, can be compared with accurate simulation base On the premise of plinth stress, applicability is stronger, computation model is relatively easy, to calculation scale Relative effect will not be produced, meets design requirement.

Computational methods of the invention are based on current specifications, result of calculation (i.e. soil rigidity coefficient) General Software for bridge analysis can be directly substituted into, for cushion cap checking computations.

Brief description of the drawings

Fig. 1 is a kind of simplified analogy method prototype structure letter of cushion cap support in great-leap-forward basis Figure；

Fig. 2 is simulation model figure of the invention.

In figure：1 --- cushion cap；2 --- stake；3 --- barrier；4 --- wait for horizontal spring 5 --- wait for Vertical Spring；6 --- wait for anti-torsion spring.

Specific embodiment

Below in conjunction with the accompanying drawings and case history specific the present invention is described in further detail.

A kind of simplified analogy method of bridge prestress cushion cap support, on simulation great-leap-forward basis When, basis is reduced to two dimensional model, direction across bridge is per campshed etc. on behalf of one, the stake and cushion cap Deng on behalf of by thrust stiffness be k_w1、k_w2、k_w3Three springs 4., 5., 6. connect, point Upper level power, vertical force and the torsion of cushion cap transmission are not undertaken.According to " m " method, meter Calculation obtains ρ_PP、ρ_HH、ρ_MH、ρ_HM、ρ_MM, and then draw the stiffness coefficient γ of a clump of piles_cc、γ_aa、 γ_ab、γ_ba、γ_bb、γ_bc、γ_cb.The stiffness coefficient that will be drawn is directly substituted into general bridge and calculates soft Part, for bridge structure correlation computations.

Wherein：

ρ_PPAxial unit displacement, stake top axial force are produced at i-th pile top；ρ_HHI-th pile top Place produces horizontal unit displacement, stake top X direction power；ρ_MHHorizontal unit is produced at i-th pile top Displacement, stake top moment of flexure；ρ_HMUnit rotation, stake top X direction power are produced at i-th pile top；ρ_MM Unit rotation, stake top moment of flexure are produced at i-th pile top.

By certain three across firm structure as a example by, middle pier cushion cap planar dimension be 34.9m+16.5m, thick 2.5m, Using C30 concrete, direction across bridge 3 is arranged, totally 8 1.8m cast-in-situ bored piles, using C30 Concrete.Cushion cap top vertical force is：63600KN, horizontal force 1966KN, moment of flexure are 28880KN. Based on the simplified analogy method that a kind of bridge prestress cushion cap is supported, advised according to existing bridge foundation Model hand computation draws.

γ_cc=3486123kN/m, γ_aa=426518kN/m；γ_bb=9341610kN/m； γ_ab=γ_ba=-1569244kN/m；γ_bc=γ_cb=0kN/m, it is compound with general Software for bridge analysis, two Person coincide good.

The present invention applies prestressed bridge foundation suitable for crossing over large obstacle and cushion cap Cushion cap support simulation.

Claims (1)

1. the simplified analogy method that a kind of bridge prestress cushion cap is supported, it is characterised in that：

When the support of great-leap-forward foundation platform is simulated, basis is reduced to two dimensional model, direction across bridge On behalf of one, stake top is k by thrust stiffness to every campshed etc._w1、k_w2、k_w3Three springs with Cushion cap bottom connects, to transmit horizontal force, vertical force and torsion；During calculating, using " m " Method solves soil rigidity coefficient gamma_cc、γ_aa、γ_ab、γ_ba、γ_bb、γ_bc、γ_cb, wherein γ_ccTo hold Platform produces vertical unit displacement, the vertical counter-force sum in cushion cap bottom；γ_aaFor cushion cap produces level list Bit Shift, cushion cap bottom horizontal reacting force sum；γ_ab=γ_baFor cushion cap produces unit rotation, cushion cap bottom Horizontal reacting force or cushion cap produce horizontal unit displacement, cushion cap bottom recurvation square；γ_bbFor cushion cap is produced Unit rotation cushion cap bottom recurvation square；γ_bc=γ_cbCushion cap produces unit rotation, the vertical counter-force in cushion cap bottom Or cushion cap produces vertical unit displacement, cushion cap bottom recurvation square；Finally soil rigidity coefficient is imported General bridge software for calculation, solves every mechanical index of cushion cap.