Study On Mechanical Behavior And Engineering Countermeasure Of Steel-concrete Composite Beam Bridge Deck Of Highway

Steel-concrete composite beam is a new type of structure developed in recent years.It has good engineering application prospects because of its light weight,high performance and good fatigue durability.However,most of the test components of composite slabs are simply supported slabs at both ends,and conventional Four-Point Loading is also adopted.There is little research on the mechanical behavior of steel-concrete composite slabs in the negative moment region.In this paper,Abaqus,the finite element software of bridge deck,is used to simulate the internal forces.The short side direction of the two-way slab is selected to study the mechanical properties of the composite beam deck in the negative moment region.According to the research direction,three 1:5 scale models with different thickness were designed and manufactured,and the finite element pre-analysis was carried out to obtain the spatial stress distribution and transmission mode of the bridge deck with different thickness;the relationship between the thickness of the bridge deck and the shear performance of the negative bending moment region;the shear nails above the beam play a pull-out role in the negative bending moment region;the thinner the bridge deck,the pull-out of the shear nails.The greater the pull-out force,the greater the result.Then static load and failure tests were carried out to find the failure modes of bridge decks under different thickness;the influence and change of the thickness of bridge decks on the stress state and ultimate bearing capacity under static load;the stress and change of bridge decks and reinforcing bars during the failure stage,and the failure loads and bending moments of different models were compared to prove that the bridge decks are safe and reliable in engineering,but at the same time the design is conservative,resulting in performance.Excess increases the cost.Finally,the failure mechanism of the two main failure modes of composite beams,i.e.fatigue shear failure of studs and tension failure of flanges of steel beams,is analyzed.Some methods for controlling cracking and coping with structural damage are summarized from the aspects of design and construction,which can provide reference for the design and construction of composite beams bridges.