In order to alleviate the problem of growing construction waste and utilize the favorable material properties of fibre-reinforced polymer (FRP), a novel form of composites, FRP-recycled aggregate concrete-steel columns (FRSCs), was proposed based on hybrid FRP-concrete-steel double-skin tubular columns (DSTCs). The composite of FRSC consists an outer FRP tube and an inner steel tube with an annular area of recycled aggregate concrete (RAC) filled between both tubes. To further investigate the compressive behavior of these composites, an experiment of Glass FRP-RAC-steel tubular long columns (FRSLCs) was performed subjected to monotonic axial compression. Three parameters were designed in the test, which are the recycled coarse aggregate (RCA) replacement ratio, the slenderness ratio and the cross-section loading method. The influence of these parameters was analyzed on the bearing capacity, lateral deflection performance and the load-strain relationship of FRSLCs. The test results show that FRSLCs have good bearing capacity and excellent ductility. Two models for DSTCs were transformed to apply in FRSLCs, which has found that Lu's model (2013) is appropriate to predict the ultimate bearing capacity of FRSLCs under the whole area loading.

Taking the free vibration system of a submerged floating tunnel tether as research object, the non-linear free vibration equation was set up. By means of Galerkin method, the partial differential equation was transformed into a set of ordinary ones. The damping ratios of the first four modes were obtained after complex eigenvalue analysis. Subsequently, effects of inclination, sag, initial tension force and length of tether on its modal damping ratios were analyzed. The results show that inclination and sag of tether merely affect the damping ratio of first in-plane mode; they have no effect on the damping ratios of higher order in-plane modes and out of plane modes; the first in-plane modal damping ratio of tether is in direct proportion to its inclination, whereas in inverse proportion to its sag; the first modal damping ratio of tether (both in-plane and out of plane) is in direct proportion to its length, whereas in inverse proportion to its initial tension.

To study the vibration response of submerged floating tunnel tether under the combined action of vortex-induced vibration and parametric vibration, a non-linear vibration equation based on wake oscillator model is set up taking the geometric nonlinearity of tether into account, in which effect of tube on tether is simplified as axial excitation. An approximate numerical solution of planning submerged floating tunnel tether is obtained by applying Galerkin method and Runge-kutta method. The variation degree of mid-span displacement response and axial force of tether is analyzed when the vortex-induced resonance and parametric resonance occur. The results show that, when vortex-induced resonance and parametric resonance occur simultaneously, the mid-span displacement and axial force of tether increase dramatically; the tether sag effect results in the asymmetry of tether mid-span vibration amplitude.

To study the nonlinear mechanical characteristics of reinforced concrete shear wall structures under rare earthquakes, a single reinforced concrete shear wall model is established in SAP2000 program, which is simulated by nonlinear multi-layer shell element. Nonlinear static pushover analysis of the model is presented by uniform acceleration lateral load pattern and inverted triangle lateral load pattern. The relationship curve between base shear and top displacement of shear wall, and the stress distribution diagrams of the concrete layer and rebar layer are obtained. It may be concluded that, the yielding of rebar layer and the cracking of the concrete layer may be observed by stress distribution diagrams. SAP2000 program is feasible to nonlinear simulation of shear wall structures.

In this paper, we studiedthe stage machinery noise in theatre by simulation and measurement. Theconclusion proposed in this paper shows that the region closed to proscenium ismore representative when evaluating or measuring stage machinery noise.Therefore, during the measurement of stage mechanical noise, it is better tochoose the first row of stalls as the representative area than only the middle seatwhich is specified in recent standards and specifications.