Expert system for prestressed concrete bridge design

The development of an expert system, BRIDEX, for the design of prestressed concrete bridges is discussed in this paper. Design of multi-span continuous pre-stressed concrete bridges pose considerable difficulties to designers because of the large number of parameters involved and their complex interactions. The design is often perceived as an iterative process of generation, evaluation and modification of trial designs. It takes years of experience to develop an understanding of the design process. BRIDEX is aimed at providing guidance to the designers by suggesting appropriate range of values for the design parameters. The knowledge within BRIDEX is mainly based on fundamental principles developed by a careful study of the intricacies involved in the design process, while heuristics are used only to supplement this knowledge. The BRIDEX approach ensures that the whole design evolves sequentially as the design proceeds, module after module.

Centrifuge tests investigating inclined grout micro-piles as a method of liquefaction remediation for existing buildings

This paper presents a series of centrifuge tests carried out to investigate the performance of non-structural inclined micro-piles as a potential liquefaction remediation method for existing buildings. Both a single-degree-of-freedom frame structure and a two-storey, two-degree-of-freedom frame structure were used as model buildings in these tests. Centrifuge tests were carried out with and without micro-piles in the foundation soil for each structure. Results primarily from the tests with the SDOF structure are presented in this paper. It is found that the micro-piles have some beneficial effect by increasing shear strains in the soil in their vicinity and hence causing dilation in these zones. However, they also increase structural accelerations by transmitting accelerations from deep in the soil and the beneficial effects from increased dilation are outweighed by the detrimental migration of pore pressures.