Grillage Analysis of a Simply Supported Bridge Under Varying Skewing Angles and Span Lengths

• Published in: Lecture Notes in Civil Engineering
• Main Author: Subki N.E.A.; Mansor H.; Kamarul Zaman N.Q.N.; Sahol Hamid Y.
• Format: Conference paper
• Language: English
• Published: Springer Science and Business Media Deutschland GmbH 2024
• Online Access: https://www.scopus.com/inward/record.uri?eid=2-s2.0-85181982958&doi=10.1007%2f978-981-99-6018-7_32&partnerID=40&md5=e2a5dcf711afb93248373d7f743dcde4

Modern highways are designed to be as straight as possible to accommodate greater speed and safety in today’s traffic. However, it is impossible to arrange for a bridge to span straight to the feature it crosses, especially when a relatively straight roadway alignment is required. Here, a ‘skew’ bridge is needed, but it will have a greater span length and create an angle at the support, the implications of which have received little attention in the current literature. The linear static behavior of a simply supported bridge with skewing geometry was investigated in this paper, and the effect of skew angles and their influence on the internal forces of the U-beam bridge at three different span lengths were observed. A three-dimensional (3D) grillage model of the proposed U-beam bridge was created in the STAAD.Pro software. Three different span lengths (15, 20, and 25 m) were investigated at three different skew angles (0°, 15°, and 40°), totaling nine grillage models studied. The BS 5400 and BD37/01 were used to design and analyze the bridge. The variation of bending moment and shear force was investigated using various skew angles and span lengths. The analysis has revealed that a non-skewed bridge behaves similarly to a one-way simply supported slab, in which load was transferred directly to the support. The analysis also showed that a skewed bridge developed a high shear force that was concentrated at the obtuse corners of the bridge deck. The load distribution of a skewed bridge was based on the shortest distance between the supports, which was located in between the obtuse corners. The grillage analysis was extended to a parametric study to further investigate the behavior of bridges under varying span lengths and skew angles. The study found that skew angle variation had a greater impact on bending moment demand and shear force demands than span length variation. This study also revealed that a bridge with a relatively low skew angle, specifically 15° or less, can be treated as a non-skewed bridge because the bending moment and shear force demands were found to be comparable. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd 2024.