Research On Continuous Deflection Mitigation Measures Of Continuous Rigid Frame Bridge

In this paper,a bridge is used as the engineering background to carry out research on measures to reduce the continuous deflection of prestressed continuous rigid frame bridges.The main research of the paper is as follows:(1)Contrast and analyze the deflection of the span of the bridge and the internal force changes of the key section under the different use ranges of high-strength light aggregate and sub-high-strength light aggregate,and determine the reasonable use range of light aggregate under the principle that the amount of deflection is the control variable.The research results show that the introduction of high-strength lightweight aggregate concrete in continuous rigid frame bridges can reduce the deflection value of the bridge’s main span.Different distribution ranges of high-strength lightweight aggregate concrete will also have different effects on deflection changes.The use of LLC60/L is about 0.37.After determining the optimal use range of high-strength lightweight aggregate concrete in the main beam,the reasonable use range of sub-high-strength lightweight aggregate is further determined.Finally,the use of high-strength lightweight aggregate is selected.When the range of LLC60/L=0.37 and the use range of sub-high-strength light aggregate is LSC60/L=0.14,the mid-span deflection control and the optimization of the internal force of the critical section are optimized;the appropriate amount of high-strength lightweight aggregate concrete can effectively reduce the bridge deflection value,In order to extend the service life of the bridge;under a variety of load effects,the deflection of the ordinary concrete bridge is lower in amplitude and rate than the test bridge using lightweight aggregate concrete.(2)Relying on the project as the research object,by co MParing and analyzing the effects of different secondary tension positions,tension amounts and tension times on the mid-span deflection of the bridge span and the internal force of the critical section,the second amount was determined using the deflection amount as the control variable.The most reasonable tensioning plan for batch prestressing.The study found that: When making the second batch of tension decisions for similar bridges,the optimal tension position for the mid-span should be the construction number block before the bridge’s dead load bending moment;the optimal tension for the mid-span is the mid-span floor22% of the total amount of beams;the optimal tension time for mid-span is one year after the bridge is completed.(3)Under the combined action of dual variables of light aggregate and secondary tension,the deflection and internal force changes of high-strength lightweight aggregate continuous rigid frame bridge based on secondary tension are studied.The study found that when two methods of restraining mid-span deflection are applied at the same time,the effect of restraining the deflection of the mid-span deflection of the supporting bridge is more obvious,and at the same time,the internal force of the structure is kept at a reasonable state for a long time,which is beneficial to prolong the normal operating life of the bridge.