Different sized/shaped micro protrusive lens arrays atop poly(methyl methacrylate) can be fabricated by a simple two-step method, i.e., indentation followed by immersion in ethanol. Profile and projection of obtained microlenses were characterized. Thermal stability of microlenses was examined at 25°C and 60°C. This work demonstrates a cost effective approach for massive fabrication of microlens array with high reliability.

This study found that it is improper to use equivalent concrete webs (ECWs) to replace corrugated steel webs (CSWs) in the MIDAS Civil. To reflect the mechanical performance difference of CSWs in different directions, a more precise theoretical model, the assimilated orthotropic plate (AOP), is presented to simulate CSWs. 3D Finite element analysis demonstrates that the AOP model can yield a more precise description of CSWs compared with the ECW model in MIDAS. In addition, this paper presents a unified calculation method for bending deformation suitable for the analysis of beams with equal-area or variable-area cross-sections, in which the non-prismatic beam is made equivalent to the prismatic beam by introducing the concept of equivalent inertia moment. Additionally, the formula of shear deformation in a non-prismatic box girder with CSWs is also derived with Timoshenko beam theory. These derived formulas for non-prismatic box girder with CSWs agree well with the numerical and measured data.

No abstract

No abstract

Recent high-profile failures of high-strength bolts – including the fatal Vivekananda Flyover collapse in Kolkata in 2016 – serve to highlight the ongoing risk of failure of such bolts. Based on investigations into continual high-strength bolt failures on steel truss bridges in China, this paper discusses and summarises the typical reasons for failure and what can be done to prevent it. Bolt quality defects, over-tightening during assembly, fatigue loads and environmental corrosion are identified as the main causes. The characteristics of bolt failure damage are highlighted and preventative measures to help reduce the risk of failure are proposed.