Application of Traffic Loading in Southern Africa Code System for Conventional Bridge Design

Abstract:
More and more Chinese companies are participating in infrastructure projects such as highways around the world, which increasing requirements for Chinese engineers and technicians to master and apply design specifications in different countries and regions. This paper, based on the Maputo Bypass Project in Mozambique, introduces traffic loading defined in SATCC (Southern Africa Transport and Communications Commission) Code comprehensively, and compares it with which in Chinese Code system. Through calculation and analysis of the actual prefabricated bridges with medium and small spans, the differences of the internal force effect due to the two types of vehicle loads are obtained. The main research conclusions: The number of lanes specified in SATCC is more conservative than in the Chinese code. The NA uniform lane load in SATCC is about 2.4 to 4.9 times that in Chinese code, and the NA axle load is 0.32 to 0.45 of Chinese code. The NB load in SATCC can be used as a vehicle load globally and locally for the structural analysis. The wheel load, axle load and total weight of BN36, for instance, are 1.286, 2.571, and 2.618 times of Chinese truck load respectively. The combination factors of SATCC traffic loads are generally greater than those of Chinese code, but traffic loads are not considered with some particular effects simultaneously in certain load cases in SATCC. The difference of the hogging moment effects of the continuous beam section above piers between the two codes is the most significant, which makes the main difference for the bridge design. The internal force effects produced by traffic loads of SATCC are greater than those of Chinese code. However, the gap narrows down as the span of beam increases. Abovementioned conclusions are as references for the design of conventional bridges in southern Africa.