Seismic Retrofit

Soft Story Retrofit

We are a team of highly seasoned engineers and experts in the field of soft story retrofit. Starting from conceptual design and estimation of construction & engineering fee, to preparing calculation & retrofit design. We take care of every step of the way until delivering a prompt & cost effective retrofit design. There are challenges in every step, which only an expert will be able to overcome efficiently and in a timely manner. High quality engineering with close attention to all existing conditions of the building will reduce the risk of delays in construction and cost and problems associated with it, significantly. During the initial site investigation all affecting conditions of the building, such as existing utility lines, sewer, power and existing framing and foundations are documented and considered in the design. A comprehensive research is done on the building permit history and original construction documents, to be used to exempt the building from mandatory retrofit requirement if applicable or to be used for the retrofit design, if the building is determined not to be exempt from ordinance. All zoning regulations applicable to the building which will have impact on the retrofit design are investigated in order to be considered in the design. Effects of skipping any of the aforementioned measures will not be immediately obvious on the retrofit calculation and drawings, however any of them might contribute to delay in construction and will be associated with change orders on design and construction and will lead to large financial burden on building owners.

Non-Ductile Concrete Retrofit

Non-Ductile Concrete structures pose a significant risk to the lives of residents in case of a seismic event. The poor detailing and lack of confinement in the reinforcement makes these type of structures susceptible to sudden and catastrophic failure. There are number of southern California jurisdictions that have passed retrofit ordinance for such structures or are in the process of adopting one. Contact us for a quick evaluation of your concrete structure and recommendations to improve the performance. Our team can offer non-linear static and dynamic analysis procedure to retrofit concrete structure with lowest possible cost to the owners. We can offer a performance based engineering approach to precisely evaluate existing structure, and identify its deficiencies. Then we move on to design options to retrofit the deficiencies. The retrofit of a concrete structure could be deficiency based  or a systematic rehabilitation. ASCE41 is the reference standard used for performance based engineering and design, while for prescriptive design ASCE7 is the governing standard.

Pre Northridge Steel Moment Frame Retrofit

Steel Moment Frame design and detailing have evolved in the recent years, ductile connection behavior and beam / columns ductility checks are added to standards and the common mistakes of CJP backing bar welding are prohibited by the AISC. Most, if not all, of these improvements have been made after Northridge earthquake in 1994, where the steel moment frames demonstrated less than expected performance. The design, detailing and fabrication drawbacks  were identified, then quality assurance measures along with design and detailing requirements were introduced in AISC to address them.

In southern California, while seismic retrofit projects on wood soft story buildings are being done in large numbers, unfortunately there are NEW steel moment frame that are being erected to retrofit the wood soft story building, while they still are designed, detailed or fabricated having some of the deficiencies of pre-Northridge  moment frames. It would be extremely counter intuitive and embarrassing for all the parties involved in a retrofit project, if a new moment frame meant to mitigate the soft story irregularity of a building, needs to be retrofitted to meet current standards of steel moment frame. This is an alarming reality that needs to be taken seriously.