Study On Crack Resistance Method Under Negative Moment Area In Steel-Concrete Composite Girder

Steel-Concrete Composite Continuous Beam Bridge have a greater negative bending moment at the supports, concrete bridge deck due to withstand large tensile stress, prone to cracking. Concrete slab cracking due to negative moment zone quit working, so the stiffness composite beams weakened. If the crack is large, harmful substances may seep through the cracks to the concrete, serious corrosion, corroded reinforced, reducing the durability of composite beams, more difficult to maintain conservation efforts. Therefore, under negative moment, for the study of the development of continuous concrete slab crack, distribution, control methods and continuous composite beams carrying capacity, slip effect is very necessary.Paper relies HZMB shallow non-navigable bridge engineering background, steel-concrete composite beam negative moment area of anti-crack resistance methods were investigated:①introduced the steel- concrete composite beam development situation, current research on structural cracks. It discussed the expansion of micro fiber concrete, combined with pivot forced displacement method and prestressed steel beam crack resistance of these three methods to HZMB project background details of the construction process to convert composite beam system, top off the beam construction, deck combinations, and focuses on the construction process and Drop and prestressed beams, and pay attention to such matters. Conversion of the system to make the overall summary.②process of lifting the finite element theory calculation, the measured data and theoretical calculation of finite element analysis results were compared, for synchronous lifting construction process played a role in effective control. The structure of computing, measured data analysis to get the top off the beam and prestressed crack resistance effects of two methods of crack resistance.③ from the experimental starting, this paper tested HZMB main steel beam composite stage to keep the beam phase(support to two four-point support), lifting down phase(system conversion phase) relative sliding of the two conditions. Steel beams and concrete law had slip flange plate interface via Dial Gauge, had the law by vibrating wire strain sensors and strain gauges measure.④through the deck deflection system conversion phase, the stress, steel-concrete relative slip to analyze and control. And leads to innovation of this paper- including reinforced concrete structure FRP crack resistance layer. Based on fracture mechanics, fracture mechanics analysis of the two crack resistance mechanism FRP reinforcing layer and draw advantage FRP reinforcing layer crack resistance. Laboratory were pasted crack resistance FRP reinforcing layer specimens plain concrete specimens were measured and analyzed flexural strength and force properties. Crack resistance proved FRP reinforcing layer has a higher carrying capacity, including cracking load and ultimate bearing capacity enhancement layer FRP crack resistance compared with plain concrete trabecular meshwork have been greatly improved.