Long Span Arch Bridges in India: Design Aspects and Aesthetics

Abstract

Good engineering design and aesthetics are synonymous. Arches have been used throughout the ages as structural elements and considered to be one of the most competitive options from aesthetic perspective. Five examples of bridges from India highlight the effectiveness of engineering design simplicity in the remote hilly region of North East India. The working season in such areas is less than six months in a year. The velocity of flow is also very large. Providing intermediate pier supports has created problems like tilting of piers, including foundations, due to erosion at many locations in such areas. Site specific structural design and aesthetic solutions using arch bridges have been worked out for following bridges:

• 1. Tharia Bridge over river Wahrew, Meghalaya, Steel Arch span 165 m

• 2. Tlawng Bridge on NH 44A, Mizoram, Steel Arch span 100 m

• 3. Sanjenthong Bridge at Imphal, Steel Bow String Girder Span 56 m

• 4. Wahjapuh Bridge, Meghalaya, RCC Arch Span 62 m

• 5. Kalipai Bridge, Meghlaya, RCC Span 79 m

In all the above bridges, proportion, order and symmetry are well applied and the structures so produced have aesthetic value. A steel intensive scheme for the arch superstructure has been adopted for Wahrew, Tlawng and Sanjenthong Bridges to solve site constraints of less working season and very high velocity of flow, to improve the aesthetics and to take advantage of the lightness of the structure whilst erecting and improving seismic performance of the structure. Wahjapuh and Kalipai are designed as RCC Arch Bridges.

Design Criteria for preserving existing landscape, complementing and even enhancing the settings have been given weightage. Various components are designed to work together and complement each other visually with aesthetics integral to the design. Five important aspects such as form, character, detail, scale and proportion have been considered from first principles. The bridges should stand as proud inheritor of Indian tradition of bridge design and construction.