Practice Periodical on Structural Design and Construction

Automatic sprinkler systems are considered to be one of the most important facilities for providing people with safety and protecting a structure and its contents from fire. Even old high-rise buildings are required to upgrade to fire safety provisions by installing sprinklers. In this paper, a comprehensive methodology for the design process of sprinkler systems is presented. Specifically, the paper discusses: (1) the requirement for automatic fire suppression systems according to the building groups, occupant load, or fire area and its location vis à vis the discharge level; (2) the design and installation of automatic sprinklers; and (3) the use and maintenance of automatic sprinkler systems. The attempt is to consolidate various principles for sprinkler design and to propose further enhancement on the practical issues related to design by integrating it with other mechanical, electrical, and plumbing systems, devices, and fixtures. Furthermore, practical recommendations are provided along with a brief discussion on alternative solutions.

A practical solution for offshore heavy lift rigging analysis using spreadsheet is presented in this paper. The procedure employed is based on the stiffness method with nonlinear geometrical considerations. The method is able to consider variations in the location of the center of gravity and slings make up in a quick and rational manner. The spreadsheet uses embedded visual basic macros to perform most of the computations. Parametric studies of heavy lifts can be performed easily using the spreadsheet to assess the sensitivity of the variables of the lift system. A simplified direct equation for skew load factor is proposed based on the results of the parametric studies.

This paper briefly introduces the present situation of concrete filled steel tube (CFST) arch bridges in China. More than 200 CFST arch bridges were investigated and analyzed based on the factors of type, span, erection method, geometric parameters, and material. Some key issues in design calculation were presented, such as check of strength, calculation of section stiffness, and joint fatigue strength. It will provide a comprehensive reference of CFST arch bridges for the bridge designers and builders.

This paper presents the outcome of an engineering study as part of the design and development of a lean and agile construction system and in particular its supply chain component. This combines modular assembly with a postponement function to be tested on a case study project (not reported here), the objective of which is to improve health, safety, and productivity for the company sponsoring the research. The contribution to research is the combination of countermeasures described in this paper that have been developed and incorporated into a wider construction system, in the same way that manufacturing has used this strategy with great success. A further output is the development and use of an innovative method for assembling, transporting, and installing mechanical and electrical modules, whereby modularization can be achieved with or without offsite manufacturing capability. The research forecasts a reduction of onsite labor of 35% compared to using traditional methods of construction, with less onsite operatives at risk of injury carrying out simpler assembly tasks within ergonomic mobile work cells. Further research is proposed to measure the benefits of the construction system following its implementation on a case study project.

This paper presents the details of an innovative external prestressing technique for strengthening of prestressed concrete girders. The technique has been developed for anchoring the external prestressing to the sides of the end block. In the proposed technique, transfer of external force is in shear mode on the end block and the required transverse prestressing force is smaller compared to conventional techniques. In order to validate the technique, an experimental investigation has been carried out on two posttensioned end blocks (EB-1 and EB-4). Steel brackets are provided on either side of the end block for transferring external prestressing force and these are connected to the anchor blocks by expansion-type anchor bolts. Performance of the end blocks has been studied for design, cracking, and ultimate loads. A ductile failure is observed in EB-1 whereas a sudden failure is observed in EB-4. The slip and slope of the steel bracket have been recorded at various stages during the experiment. These values are found to be smaller in EB-1 than in EB-4 due to a higher anchorage depth of bolts. Finite-element analysis has been carried out by simulating the geometry, loading, material nonlinearity, and test conditions. Linear and nonlinear static analysis has been conducted for the specified loadings and the responses have been compared. From the analysis, it has been observed that the computed slope and slip of the steel bracket are in good agreement with the corresponding experimental observations.