Bridge-grid is a type of steel grid decking used in bridge construction. It consists of a series of welded steel bars arranged in a grid pattern, typically used either as a stay-in-place form or as the final riding surface. nstruction of steel bridges. The more recent editions of the Handbook were developed and maintained by the Federal Highway Administration (FHWA) Office of Bridges and Structures as FHWA Report No. These grid deck systems are also very lightweight and durable, often times weighing 30-50% less than conventional concrete decks and still. This handbook covers a full range of topics and design examples intended to provide bridge engineers with the information needed to make knowledgeable decisions regarding the selection, design, fabrication, and construction of steel bridges. Each standard. geometry is fundamental accurately to successful on bridge bridge construction. and detailed Detailed drawings superstructures to engineers and technicia at a specific substructures. Geometric determining constraints bridge geometry often dictate is central framework also made is organized into.