In general, post–installed adhesive anchor design per ACI 318 Chapter 17 is relatively straightforward. In practice, however, post–installed anchorage can often become challenging because of fast–track project schedules, supply issues, ever-changing weather conditions, design conflicts/changes, or unexpected field conditions.
Structural engineers for the Rose Avenue Elementary School project in Oxnard, California, a high seismic zone, chose to switch from special moment frames requiring welded connections to the Simpson Strong-Tie Yield-Link moment connection, which features bolted connections instead of onsite welding. This case study shares the experiences of structural engineers, fabricators and other project partners utilizing this innovative solution for structural steel construction.
Over the next few months, I will be doing a short three-part series going over common technical inquiries we receive in the engineering department. There is a wealth of information available on our website and in our literature, but so much content can sometimes be difficult to navigate. It is often said that knowledge is power, so my hope is to empower you with all the technical support you need so you can complete your job quickly and efficiently.
Modern construction schedules and conditions create a demand for solutions that can perform in a wide variety of environments. In the following post, Field Engineer Chris Johnson provides a rundown of different concrete and hole conditions for adhesive anchoring, the related design factors, and proper installation instructions and approved adhesive products for submerged anchorage.
Strengthening of shear walls and diaphragm-to-wall connections has started on Little Tokyo Towers (see photo 1) located in downtown Los Angeles, CA. This senior–living residential facility was built in 1975. Structural analysis by Tuan and Robinson Structural Engineers showed that some modest strengthening was required to improve the building’s lateral system performance in the event of an earthquake.
Structural renovation work continues on an historic, 1920s-era theater in Hollywood, California. This major renovation will improve the structural performance of the building and help ensure that theatergoers and building occupants are safe in the event of a major earthquake. We are excited to share a second update on this project that focuses on the use of fiber-reinforced polymer (FRP) for strengthening the theater’s roof diaphragm. Continue Reading
Not all post-installed mechanical anchors are created equal. There are key differences between screw and expansion anchor types — differences that include how they gain their holding strength, installation requirements, and overall anchor performance. In the following post, field engineers Todd Hamilton, Chris Johnson and Derek Gilbert compare the two anchor types.
As a Composite Strengthening Systems™ Field Engineer at Simpson Strong-Tie, I’ve supported many composite strengthening projects from design through construction and had hands-on experience troubleshooting issues with FRP witness panels. Through these experiences, I’ve learned a few lessons and developed some best practices worth sharing with anyone in the engineering and construction communities who may encounter similar issues.
Simpson Strong-Tie and Structural Technologies formed a strategic alliance for Composite Strengthening Systems™ (CSS) products in 2021. CSS products include fiber-reinforced polymer (FRP) and fabric-reinforced cementitious matrix (FRCM) strengthening systems. Additionally, where CSS products are not a viable solution, the alliance can also offer recommendations and design for other non-CSS or conventional strengthening solutions. This alliance allows each firm to specialize in their areas of expertise:
We’re excited to share another fiber-reinforced polymer (FRP) project that required both flexural and shear strengthening (photo below) of reinforced concrete joists to enable the slab floors to carry more live load. The structure is in Southern California, and appears to have been built in the 1950s or 1960s when pan joist construction was common. The EOR for this project, Structural Focus, is an experienced structural engineering firm known for seismic retrofit solutions. The FRP applicator was FD Thomas Structural Specialties, a contractor with decades of FRP installation experience.