Roof Poding Deflection Limit

See section 1611 for rain and ponding requirements and section 1503 4 for roof drainage requirements.

Roof poding deflection limit.

In order to stay intact and in place a roof must be able to resist loads both permanent and temporary that are pushing. 5 15 ponding on roofs. The total load deflection limit is l 180 and l 480 for the roof and floor respectively. The international codes i codes are the widely accepted comprehensive set of model codes used in the us and abroad to help ensure the engineering of safe sustainable affordable and resilient structures.

When there is the possibility of water ponding which may cause excessive loads and additional progressive deflection each component of the roof system including decking purlins beams girders or other principal structural supports should be designed accordingly. According to bs en 1994 1 1 if the maximum deflection of the sheet is greater than 1 10 of the slab thickness then ponding should be allowed for. These limit states are mathematic expressed as. Deflection limits for the composite deck are given in bs en 1994 1 1 and bs5950 4.

120 it can be derived 3 that z a π so that the bending moment in the middle is. 7 752 8 4 ˆ 2 2 2 2 2 2 0 a a qa qa m q π π π 9 the first order deflection in the middle of the beam δˆ0 can be determined by considering. This simplistic criteria puts a limit of the span divided by 360 on the incremental deflection due to live or transient load only and a limit of the span divided by 240 on deflection under total load. Load limits on the roof of a building.

Roofs are under a lot of pressure. The increased slope for drainage mitigates ponding and helps prolong the lifespan of the roof cover. D ll l 360. When a 1 4 in 12 design slope is a design constraint using camber or increased member stiffness and stresses should be considered using acceptable wood.

The international code council icc is a non profit organization dedicated to developing model codes and standards used in the design build and compliance process. D tl l 240. Load deflection limit of l 120 for a roof deck whereas ibc 2015 table 1604 3 footnote a stipulates a total load deflection limit of l 60 for structural metal roofing.