Building Stronger with Natural Disasters in Mind
In recent years, the increasing number and ferocity of natural disasters has made it clear that we must continue to innovate building practices, products and update codes accordingly. We have to build smarter and build stronger.
White Cap is constantly working to offer innovative products to simplify installation. Here are some revolutionary products and techniques specifically designed to combat the destructive forces that occur during natural disasters, like earthquakes, tornadoes, straight-line winds, and floods.
Continuous Load Path - describes how wind and seismic loads are transferred horizontally and vertically through structures. Anchoring shear walls and roof trusses at each level with interconnecting fasteners and framing elements transfers the load to the foundation, creating a continuous load path for a stronger structure.
To build stronger and to meet new building codes, threaded rod tie-down systems are replacing conventional hardware. Fastened at the end of each shear wall, a structure is anchored to the foundation and will resist overturning. The threaded rods create a continuous load path and provide the necessary tension against lateral forces. To fight uplift, threaded rod assemblies are also installed from the top plate to the foundation, securing roof trusses. Threaded rods are also fastened at every floor level.
In high-wind areas like Florida, code requires that roof framing must be connected to the top of masonry walls to resist uplift forces. Many contractors have found the easiest way to make this connection is to use a strap that embeds into the top of the wall and fastens directly to the roof framing. Embedded truss anchors, available in a variety of length, are a solution.
Many popular brand manufacturers, like Simpson Strong-Tie and MiTek, offer software and published guides that list all special connector options to help you choose the right anchors and fasteners to build safer and stronger in high-wind areas. You’ll also find installation guides and tips.
Uplift Load Path - is the force that can lift a structure. When high winds blow over the top of a structure, a suction force can be created that is strong enough to lift the roof because the pressure under a roof is greater than above the roof. To prevent damage, the strong uplift forces must be transferred down to the foundation. Several connections are required to create a continuous load path. While homes are built from the bottom up, they are designed from the top down. Products and load selection for the roof will affect the products and loads for the rest of the structure including the foundation.
Lateral Load Path - occurs when high winds blow against the sides of a structure, creating such a strong force that the structure slides off its foundation. Combined with uplift forces, the shear forces can even make a structure overturn or rack. Adding bracing, connectors, and reinforced shear walls will reinforce the structure against these load paths.
Large window and door openings, including garage doors, do not provide enough wall strength to resist lateral loads. Prefab panel applications offer strong solutions and meet code requirements. Also, there is a wide range of specific connectors that can be used to complete the uplift and lateral load paths.
After years of study, many cities are committed to investing in preservation of soft-story buildings, many of which are historic, have special character, architectural significance, or simply define a neighborhood. Cities, like Los Angeles, Boston, San Francisco, and more, are mandating that buildings be retrofit to increase and maintain neighborhood survival.
Some retrofit methods include using conventionally framed wood shear walls or “moment frames,” to add strength to the soft-story structures.
Moment frames are configurations of beams and column designed to transfer the bending moment and shear forces through frame and connections to provide resistance to lateral forces. When moment frames are used to provide additional strength, without obstructing openings, engineers can select one of three types: ordinary moment frames (OMF), intermediate moment frames, (IMF), and special moment frames (SMF).
The bolted frame design allows beams and columns to be assembled in parts, reducing demolition and integrates into the project schedule much easier. Architectural impact and installation labor costs can be greatly reduced by eliminating the beam bracing.
Success of the retrofit programs has cities in vulnerable areas taking a proactive stance and developing plans to strengthen their communities before disaster strikes. Tests by local regulatory organizations have concluded that select construction innovations can strengthen existing buildings while meeting the demands of the building, its owner, and residents.
White Cap can help you find the right solution to safeguard against natural disasters. Contact your local account manager for the latest innovations.
White Cap is constantly working to offer innovative products to simplify installation. Here are some revolutionary products and techniques specifically designed to combat the destructive forces that occur during natural disasters, like earthquakes, tornadoes, straight-line winds, and floods.
Continuous Load Path
Continuous Load Path - describes how wind and seismic loads are transferred horizontally and vertically through structures. Anchoring shear walls and roof trusses at each level with interconnecting fasteners and framing elements transfers the load to the foundation, creating a continuous load path for a stronger structure.
To build stronger and to meet new building codes, threaded rod tie-down systems are replacing conventional hardware. Fastened at the end of each shear wall, a structure is anchored to the foundation and will resist overturning. The threaded rods create a continuous load path and provide the necessary tension against lateral forces. To fight uplift, threaded rod assemblies are also installed from the top plate to the foundation, securing roof trusses. Threaded rods are also fastened at every floor level.
High-Wind Preparedness
In high-wind and seismic areas, building codes require that framing for floors and roof diaphragms be connected into the side of masonry walls to prevent walls from being pulled outwardly. Masonry contractors embed PA/HPA Purlin Anchors into masonry walls where the floor or roof will be. To make the installation easier and for foolproof accuracy, embedment lines are stamped on the anchors so installers know the correct embedment level. Horizontal rebar should also be placed in the wall at the strap location; building codes require the strap to hook around the rebar.In high-wind areas like Florida, code requires that roof framing must be connected to the top of masonry walls to resist uplift forces. Many contractors have found the easiest way to make this connection is to use a strap that embeds into the top of the wall and fastens directly to the roof framing. Embedded truss anchors, available in a variety of length, are a solution.
Many popular brand manufacturers, like Simpson Strong-Tie and MiTek, offer software and published guides that list all special connector options to help you choose the right anchors and fasteners to build safer and stronger in high-wind areas. You’ll also find installation guides and tips.
Uplift and Lateral Load Path
Uplift Load Path - is the force that can lift a structure. When high winds blow over the top of a structure, a suction force can be created that is strong enough to lift the roof because the pressure under a roof is greater than above the roof. To prevent damage, the strong uplift forces must be transferred down to the foundation. Several connections are required to create a continuous load path. While homes are built from the bottom up, they are designed from the top down. Products and load selection for the roof will affect the products and loads for the rest of the structure including the foundation.
Lateral Load Path - occurs when high winds blow against the sides of a structure, creating such a strong force that the structure slides off its foundation. Combined with uplift forces, the shear forces can even make a structure overturn or rack. Adding bracing, connectors, and reinforced shear walls will reinforce the structure against these load paths.
Large window and door openings, including garage doors, do not provide enough wall strength to resist lateral loads. Prefab panel applications offer strong solutions and meet code requirements. Also, there is a wide range of specific connectors that can be used to complete the uplift and lateral load paths.
Earthquakes/Soft-Story Retrofit
Wood-framed residential and multi-family apartment buildings of at least three-stories, with a retail or garage ground floor, are known as “soft-story” buildings. When natural disasters hit major cities, it is the damage to these soft-story buildings that creates massive home loss, displacing thousands.After years of study, many cities are committed to investing in preservation of soft-story buildings, many of which are historic, have special character, architectural significance, or simply define a neighborhood. Cities, like Los Angeles, Boston, San Francisco, and more, are mandating that buildings be retrofit to increase and maintain neighborhood survival.
Some retrofit methods include using conventionally framed wood shear walls or “moment frames,” to add strength to the soft-story structures.
Moment frames are configurations of beams and column designed to transfer the bending moment and shear forces through frame and connections to provide resistance to lateral forces. When moment frames are used to provide additional strength, without obstructing openings, engineers can select one of three types: ordinary moment frames (OMF), intermediate moment frames, (IMF), and special moment frames (SMF).
The bolted frame design allows beams and columns to be assembled in parts, reducing demolition and integrates into the project schedule much easier. Architectural impact and installation labor costs can be greatly reduced by eliminating the beam bracing.
Success of the retrofit programs has cities in vulnerable areas taking a proactive stance and developing plans to strengthen their communities before disaster strikes. Tests by local regulatory organizations have concluded that select construction innovations can strengthen existing buildings while meeting the demands of the building, its owner, and residents.
White Cap can help you find the right solution to safeguard against natural disasters. Contact your local account manager for the latest innovations.