The bridge crack has the reason brief analysis Author: Order In recent years, our province transportation infrastructure obtained the swift and violent development, each place has constructed the massive concrete bridge. In the bridge construction and the use process, concerns because of appears the crack but to affect the project quality even to lead the report common occurence which the bridge breaks down collapses. The concrete dehiscence may say is "often is taken bad" and "frequently-occurring disease", is puzzling the bridge building technical personnel frequently. Actually, if adopts the certain design and the construction measure, very many cracks are may overcome and control. In order to further strengthens to the concrete bridge crack understanding, avoids in the project appearing the harm big crack as far as possible, this article the reason which and produces to the concrete bridge crack type makes the comprehensive analysis, the summary as far as possible, by facilitates the design, the construction discovers the control crack the feasible means, achieves the guard in not however function . L concrete bridge crack type, origin In fact, the concrete structural cracks origin is complex and there are many kinds of factors, even they affect it mutually, but each crack has it to have one kind of or several kind of main reasons. The concrete bridge crack type,as the reason it produced, may divide the following several kinds approximately:

First, the load causes crack The concrete bridge is static in the convention, moves the crack which under the load and the secondary stress produces to call the load crack, induces mainly has the direct stress crack, the secondary stress crack two kinds. The crack which outside the direct stress crack is refers to which the load to cause the direct stress produces. The crack produces the reason includes: 1st, design calculation stage, when structure computation does not calculate or partially leaks calculated; The computation model is unreasonable; Structure stress supposition and actual stress not symbol; The load little calculated or leaks calculated; The endogenic force with matches the muscle miscalculation; The structure safety coefficient is insufficient. When structural design does not consider the construction the possibility; The design cross section is insufficient; The steel bar establishment are few or the arrangement mistake; The structure rigidity is insufficient; The structure processes is improper; The design paper confession is unclear and so 2nd, the construction stage, does not limit piles up the construction machines and tools, the material; Did not understand the prefabricated structure structure stress characteristic, stands up from failure at will, the hoisting up, the transportation, the installment; According to the design paper construction, arbitrarily does not change the structure construction order, the change structure stress pattern; Does not make under the machine vibration to the structure the fatigue strength checking calculation and so on. 3rd, the operational phase, surpasses the design load the heavy vehicle bridge; Vehicles, ships contact, hit; Has the gale, the heavy snow, the earthquake, the detonation and so on. The secondary stress crack is refers to the secondary stress which causes by the outside load to produce the crack. The crack produces the reason includes: 1st, outside design under load function, because the things the practical work condition same routine calculation has discrepancies or the computation considered, thus causes the secondary stress in certain spots to cause the structure dehiscence. This place for example two articulations arched bridges skewback design often uses the arrangement "X" the shape steel bar, at the same time reduces the cross section size means design articulation, this place the theoretical calculation can have the bending moment, but the actual this articulation still could anti- be curved, down to appeared the crack but to cause the steel bar to rust away. 2nd, in the bridge structure needs the chisel groove frequently, opens the hole, the establishment corbel and so on, uses the accurate scheme in the routine calculation to carry on the analog computation with difficulty, the general basis experiences establishes the working reinforcement. The research indicated that, after the stress component digs the hole, the strength will flow has the diffraction, will be crowded nearby the hole, has the huge stress concentration. In long cross pre-stressed Liang, frequently in cross in needs to interrupt the steel continuously according to the section endogenic force to tie, establishment anchorage, but may see frequently nearby the anchor cross section to the crack. Therefore, if processes improper, in these tructures corners or the component shape sudden change place, the working reinforcement cutoff is easy to appear the crack. In the actual project, the secondary stress crack has the load crack most common reason. The secondary stress crack is Zhang La, the cleavage, cuts the nature. The secondary stress crack also is causes by the load, only is does not calculate generally according to the convention, but along with the modern computation method unceasing consummation, the secondary stress crack also is may achieve the reasonable checking calculation. For example now to the pre-stressed, the continuous variation and so on two secondary stresses which produces, many plane links are the finite element procedure may correctly calculate, but quite is actually difficult in 40 years ago. In the design, should pay attention