Load Paths
Home Builder’s Guide to Coastal Construction
FEMA 499/June 2005 
Technical Fact Sheet No. 10

Purpose: To illustrate the concept of load paths and highlight important 
connections in a wind uplift load path.

Key Issues
--Loads acting on a building follow many paths through the building and must 
eventually be resisted by the ground, or the building will fail.
--Loads accumulate as they are routed through key connections in a building.
--Member connections are usually the weak link in a load path.
--Failed or missed connections cause loads to be rerouted through unintended 
load paths. 

Graphic:
Vertical load path from roof to ground on a platform-and-pile-construction 
building. Note: Load paths will vary depending on construction type and design. 
Adjacent framing members will receive more load if a connection fails. 
--Link 1: High winds lift the roof upward. Roofing fasteners link the roof 
covering to the sheathing (note: although not a structural connection, the 
attachment of the roof covering to the roof sheathing is an essential part of 
protecting the building envelope), and sheathing fasteners link the sheathing to 
the roof framing members (see Fact Sheet No. 18).
--Link 2: Accumulated roof load is routed through roof-to-wall connections. 
Special roof ties connect the roof framing to the bearing walls (see Fact Sheet 
No. 17).
--Link 3: Upper walls transfer loads directly to the lower walls. The floor 
framing is bypassed by using the metal straps or extended exterior sheathing 
that directly connects upper wall studs to the lower wall studs. A similar 
connection is used to connect the lower wall to the main floor beam.
--Link 4: The accumulated uplift force is transferred from the main floor beams 
to the pile foundation with special brackets or bolts (see Fact Sheet No. 13). 
Note: some of this load is offset by the weight of the building.

Note: Horizontal load paths transferring shear from upper stories to the ground 
must also be analyzed.

If a connection fails, an alternative load path will form. If the members and 
connections in the new load path have inadequate resistance, progressive failure 
can occur. Loads must be routed around openings, such as windows and doors. 
Accumulated loads on headers are transferred to the studs on the sides of the 
openings. 

Load path around a window opening.
--Link: an adequate connection must be made between the header and the king stud 
in order for the load to continue down the path.
--Link: the bottom of a wall could have points of high uplift due to an 
accumulated load from above. Suitable hardware should be installed in the proper 
locations.

Load paths can be complex through a connection. It is important that each link 
within the connection be strong enough to transfer the full design load. 

Load path through a pile connection.
The detail at left shows a typical floor-to-pile connection. Uplift loads are 
transferred through the joint in the following order.
1.	from upper story to strap
2.	from strap to floor beam
3.	from floor beam to bolts
4.	from bolts to pile
5.	from pile to ground

[End of Fact Sheet No. 10]