Study On Layout Of Connectors For Precast Sandwich Insulation Wall

With the continuous promotion of assembled buildings,prefabricated concrete sandwich insulation exterior wall panels are more and more applied to practical projects.Connector,as an important force-bearing member connecting inner and outer blade wall panels,is an important factor affecting the mechanical and thermal properties of prefabricated sandwich insulation exterior wall panels.Its mechanical properties are related to the safety and durability of the wall.The thermal performance of prefabricated sandwich insulation exterior wall panels directly determines the thermal insulation performance and building energy consumption of prefabricated assembly buildings.For this reason,in this paper,numerical simulation of the mechanical properties and thermal properties of FRP and stainless steel connectors between inner and outer blade walls is carried out for prefabricated sandwich insulation exterior wall system.The main research contents are as follows:(1)The effective bending length of FRP connectors is simulated and analyzed,and the formulas for calculating the effective bending length of FRP connectors with different cross-section inertia moments are obtained.From the comparison of simulation results,it can be concluded that under the same thickness of insulation layer,the greater the moment of inertia of cross-section,the longer the effective bending length of the connector is.。(2)The mechanical calculation method of FRP connector and stainless steel connector for prefabricated sandwich insulation exterior wall panel is proposed.The actual wall panels with large cantilever length of outer blade wall are selected and compared with the simulation results to verify the feasibility of this calculation method.。(3)The simulation analysis of prefabricated sandwich insulation exterior wall panels with FRP connectors and stainless steel connectors under the conditions of film removal,hoisting,transportation and thermal stress is carried out.Considering the influence of inclined insertion of connectors into concrete,cantilever length of outer blade wall and thickness of insulation layer on the stress of connectors and outer blade wall concrete.The results show that the bearing capacity of the two kinds of connectors has a large safety reserve under different conditions.When the cantilever length of the outer blade wall is too long,the maximum stress of the concrete in contact with the connectors exceeds the tensile strength of the concrete,which will cause concrete cracking.Finally,through the analysis of simulation results,two kinds of optimization suggestions for the layout of connectors are put forward.(4)Starting from the thermal performance of prefabricated sandwich thermal insulation exterior wall panels,the thermal simulation analysis of prefabricated sandwich exterior wall panels using FRP connectors and stainless steel connectors is carried out.The results show that the heat transfer coefficient of sandwich exterior wall panels with FRP connectors differs little from that without connectors,and the cold bridge effect is not obvious.For sandwich exterior wall panels with stainless steel connectors,the heat transfer coefficient of sandwich exterior wall panels with 70 mm insulation layer is 7.03%different from that without connectors,and the thermal conductivity of stainless steel materials themselves is larger,which results in a certain cold bridge effect.