New AISC/SJI Design Guide Details Rain Loads and Ponding

April 15, 2024

Design Guide 40CHICAGO – The American Institute of Steel Construction and the Steel Joist Institute have teamed up to create a comprehensive reference volume for rain loads and ponding design.

Design Guide 40, Rain Loads and Ponding provides guidance for the design of roof systems to avoid or resist water accumulation and any resulting instability. It includes an in-depth review of rain loads and ponding effects to help design professionals properly and efficiently design for ponding on roofs constructed with structural steel, open web steel joists, and joist girders.

It also contains several recommended methods of analysis that can be used to consider the effects of ponding, methods of design accounting for ponding effects, and a presentation of the SJI Roof Bay Analysis Tool, along with plenty of design examples that illustrate the concepts discussed.

Mark D. Denavit, PE, PhD, associate professor at the University of Tennessee, Knoxville and James M. Fisher, PE, PhD, emeritus vice president of CSD Structural Engineers, wrote the design guide. 

Design Guide 40 is now available for download at Like all digital design guides, it is free for AISC members.


For more information contact:

Dani Friedland
Director of Marketing Communications

American Institute of Steel Construction

The American Institute of Steel Construction, headquartered in Chicago, is a non-partisan, not-for-profit technical institute and trade association established in 1921 to serve the structural steel design community and construction industry. AISC's mission is to make structural steel the material of choice by being the leader in structural steel-related technical and market-building activities, including specification and code development, research, education, technical assistance, quality certification, standardization, market development, and advocacy. AISC has a long tradition of service to the steel construction industry of providing timely and reliable information. 

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