A cable dome is a form of cable-strut tensegrity structure, which is popular for long span membrane roof structures. However, there is an opportunity for its major development for a wider range of applications if rigid roof cable dome structures can be achieved. In this paper, we propose the tensile beam-cable dome (TBCD), a new type of space structure based on the features of the cable dome. By changing the ridge cables to hinged tensile beams, a structure can easily be covered with a rigid roof. We introduce its configuration and mechanical characteristics, and put forward four categories of this structure with hinges set at different locations on the tensile beams. In addition to achieving the aims of tow-lifting and tensioning construction, the integral tow-lifting method is presented for TBCD, and the nonlinear dynamic finite element method (NDFEM) of form-finding analysis is introduced for the overall construction analysis. For integral tow-lifting construction, the mechanism hinges should be set at the middle of the tensile beams to make the tensile beam grid into a mechanism system. Through construction analysis of seven mechanism hinge distribution modes, the modes with mechanism hinges set only on the middle or inner tensile beams were optimal.

The static drill rooted nodular (SDRN) pile is a new type of composite pile that consists of a precast pile and surrounding cemented soil. Its cost advantages and environmentally friendly construction have been proven in applications in Southeast China. Moreover, the composition of pipe pile and nodular pile is based on the load transfer mechanisms of a pile foundation, which is effective in optimal design. This paper presents a field study on the behavior of SDRN piles under compression. The load–displacement response, axial force, mobilized load of pile cap, skin friction, and tip resistance of the composite pile are discussed. Here, the bilinear base load–displacement model was adopted to analyze the test results. It is found that providing caps on the static drill rooted piles takes full advantage of the static drill rooted method, and drilling and grouting into the soil beneath the cap, which can be considered a type of ground improvement treatment, can increase the bearing capacity of the pile cap; thus, setting a pile cap for this type of piles is recommended. The existence of the caps in the field tests decreased the skin friction of the upper part of pile shaft because of the additional settlement of the surrounding soil, which developed owing to the pressure from the caps. The frictional capacity of the concrete–cemented soil interface was much higher than that of the cemented soil–soil interface. The skin friction of the lower part of the pile shaft was about 1.25 times in clayey soil and 2.0 times in sandy soil compared with the bored pile. It can be concluded that the cemented soil–soil interface of the SDRN pile was probably better than the concrete–soil interface of the bored pile. The test results fitted the first stage curve of the bilinear model well, and it can be supposed that the base soil was strengthened because of the permeation of the cement paste.

This paper presents the results of an experimental and numerical study of the compressive capacity of longitudinally cracked wooden columns retrofitted using self-tapping screws. The screws were driven into the wood perpendicular to the wood grain to alleviate the propagation of existing cracks and to improve the structural integrity of the cracked columns. Full-scale concentric and eccentric compression tests were conducted to investigate the failure modes and maximum load carrying capacity of such columns. A 3D finite element model was developed, verified, and then used for a parametric study. The test results indicated that the cracks (of 6 mm wide) caused a resistance loss of up to 19% compared with an intact column, but most of this resistance loss can be remedied by using self-tapping screws. It was also found that such resistance loss and recovery are dependent on the seriousness of the cracking, and generally increase with the increased initial mid-height deflection and decreased screw spacing, whereas a screw spacing of 100 mm would be sufficient for most cases considered in this study.

Cement asphalt mortar (CAM) softening is a common phenomenon that results from ageing and rain soaking when a high-speed railway is in service. CAM softening seriously affects vehicle operation safety and track dynamics. In this paper, a 3D coupling dynamic model of a vehicle and a China railway track system I (CRTS-I) slab track is developed. By using the proposed model, the wheel-rail contact forces, derailment coefficient, wheelset loading reduction ratio, and the track displacements are calculated to study the influences of CAM softening on the dynamic characteristics of a vehicle-track system. A track-subgrade finite difference model is developed to study the effect of CAM softening on track damage. The results show that track interface shear failure develops when the CAM softening coefficients reach 10–100. The CAM softening coefficient should not be less than 1000, otherwise a high-speed running vehicle may risk derailment.

In this study, we conducted numerical simulations of fluid resonance in-between two floating structures based on potential theory assessing the effect of fluid viscosity by including the artificial damping force. The numerical results of two adjacent Barges systems and Barge & Wigley systems were compared with experimental data of those of the viscous fluid model based on Reynolds average Navier-Stokes equations (RANSE). It can be observed that the conventional potential flow model (without artificial damping force) significantly over-estimated the wave height and forces around the resonant frequencies. Results of the present method with an appropriate damping coefficient supported the available data, confirming the importance of the viscous damping effect on strong hydrodynamic interaction between the floating structures. Furthermore, influences of lateral clearances, wave heading angles, and ships’ motions on the wave surface elevations were analyzed. Validation and application of methods to estimate the fluid resonant frequencies and modes were also conducted. Generally speaking, Molin’s simplified theory can give an accurate estimation of resonant frequencies and serve as a practical tool to analyze the fluid resonant phenomena of gaps in-between a two Barge system and Wigley & Barge system in close proximity.

This paper pertains to case drain pressure limitation for axial piston swashplate pumps used in open-loop circuits. The critical case drain pressure for pumps of this type is considered from the oil film perspective of the slipper/swashplate pair: (1) height of the lubricating oil film, (2) supporting stiffness, and (3) location of the centroid of the equivalent hydrodynamic lifting force. A dynamic lubricating oil film simulation model is established to determine the critical case drain pressure for which the slipper cannot remain in a stable state. Based on the simulation results, the worst condition occurs at the point when the height of the lubricating oil film is the maximum, the supporting stiffness is the minimum, and the distance between the centroid of the equivalent hydrodynamic lifting force and the bottom center of the slipper is the maximum. The slipper is stable only when the difference between the case drain pressure and the suction pressure is within a reasonable range. Subsequently, a design criterion is put forward to specify the reasonable case drain pressure, and this is validated by experimental results.