Experimental Research On The Thick Pile Caps Of Railway Bridge

Beaucase of the high bearing capacity, less settlement and good seismic performance,pile foundation is widely used in the construction of the railway bridge in our country. Itshould be attached in the design for that pile caps is the essential role in the pile foundation,and an important part of ensuring that the force along the power transmission path transfer.Therefore, it has very important engineering reference value and theoretical significance forpile foundation bearing capacity of pile cap. Traditional design method of pile foundation pilecaps is based on the theory of beam and plate bending, which has many deficiencies. With thedeepening of research, the scholars at home and abroad put forward various transfer modes ofthick pile caps, among which the spatial truss model (tension and compression rod model) isconsidered the most conforms to the transfer mechanism of pile caps. Cap space truss modelhas been proposed, but force mechanism and mechanical characteristics have not beenreached an agreement, nor unified calculation formula established.The design method of thick pile caps, at rules or regulations of our country andabroad,does not have a accurate force transmission way.So we have to increase the thicknessof the pile caps so that it is safe enoughly.But a lot of thick pile caps appear.This way not onlywaste a lot of material, but also lost a lot of material resources and manpower. Therefore,it isvery important to have a comprehensive understanding of cap space power transmission mode,and a complete calculation method of pile caps.Then,we can further understand the functionsof pile caps, construction design of pile caps safely, reduce the project cost.All above, thistopic researches the force mechanism of thick pile caps about railway bridge pilefoundation.It has a great significance both in theory and engineering practice.This paper explores the stress characteristics and power transmission mechanism of thepile caps of railway bridge eleven pile caps through field experiment research and finiteelement model analysis.The main research content as those:(1) Synthesizing domestic and international relevant research results, analyze theinfluence factors of railway bridge pile foundation bearing capacity of thick pile caps. Themain influencing factors includes concrete strength, reinforcement methods, at the bottom ofthe pile caps is apart from the thickness ratio, effective thickness of pile caps, etc.(2) Embeding steel bar inside the pile caps, test the the pile caps stress in bridge majorconstruction stage many times in a row. Though the ANSYS,we can set up the equivalentfinite element model of11pile caps at construction stage, then compare and analyze thetheoretical calculation and the measured results,and study stress propagation characteristicsof each construction stage of pile caps. (3) Comparing the studying of the finite element model to different influence factors,so that we can analyze the stress mechanism of pile caps and put fo rward the reasonableoptimization scheme of pile caps.