Existing Concrete Building Assessment following Vertical Expansions
Credits: 8 PDH
PDH Course Description:
What happens when an existing concrete building is vertically expanded, its original structural role is changed, and the new load path begins to show signs of distress?
This course takes the participant inside a real-world structural assessment case involving an aging reinforced concrete workshop building modified by removing its original roof, adding a new slab-and-beam floor, and introducing planted columns over existing long-span frame girders. What appeared to be a straightforward vertical addition developed into a complex structural safety problem involving unintended transfer girder behavior, excessive deflection and cracking, unreliable added supports, foundation overstress, corrosion, settlement, and seismic vulnerability.
Developed from the perspective of the consultant who carried out the analysis and evaluation of the case, this is a consultant-led, forensic-style assessment course rather than a conventional design course. It goes beyond equations and code checks to focus on the judgment required to interpret distress, question assumptions, verify load paths, and assess foundation reliability, following the full process of field observation, material testing, structural modeling, demand-capacity and serviceability evaluation, and final safety recommendations. A central lesson is that adding supports or strengthening members does not automatically make a structure safe unless the complete load path, from the new loads down to the soil, is verified; in some cases, the safest solution is not to strengthen an overloaded and unreliable system as-is, but to remove unsafe added loads and restore a more reliable load path before strengthening only what truly requires it.
This course is especially valuable for engineers involved in existing-building evaluation, renovation, vertical additions, structural rehabilitation, forensic assessment, and peer review, addressing practical problems rarely covered in conventional courses—planted columns over existing girders, questionable retrofit measures, and the difficult decision of when load removal may be safer than strengthening. By completing this course, participants will be better prepared to evaluate existing concrete buildings after vertical additions, verify altered load paths, interpret structural distress, and make defensible decisions regarding load removal, strengthening, repair, monitoring, and continued use.Topics:
By the end of this course, participants will be able to:
- Identify how vertical additions can alter gravity demand, seismic mass, occupancy requirements, foundation reactions, and the original load path of an existing concrete building.
- Evaluate how planted columns and concentrated reactions can transform existing long-span girders into unintended transfer members.
- Interpret structural distress—including deflection, cracking, joint distress, corrosion, settlement, and tilt—as evidence of altered structural behavior rather than isolated defects.
- Integrate field observations, material testing, structural surveys, geotechnical information, and monitoring data into a defensible existing-building assessment.
- Develop and compare analytical scenarios representing the original structure, the modified building, the distressed condition, load-reduced alternatives, and proposed strengthening schemes.
- Assess distressed reinforced concrete girders, columns, joints, and supplemental supports considering strength, stiffness, serviceability, load-transfer behavior, and observed condition.
- Verify the complete load path through planted columns, transfer girders, existing columns, added supports, foundations, and supporting soil.
- Evaluate foundation reactions and soil-bearing pressures as part of the overall feasibility of retaining or strengthening a vertical addition.
- Compare load removal, load reduction, local strengthening, foundation strengthening, repair, monitoring, and use restrictions as alternative rehabilitation strategies.
- Develop practical engineering recommendations that define required intervention, monitoring, occupancy limitations, rehabilitation priorities, and restrictions on future structural modifications.
To take this course:
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Intended Audience: This course is intended for structural, civil, and forensic engineers, along with building officials and technical reviewers, who assess, rehabilitate, or approve modifications to existing concrete buildings involving altered load paths, transfer girders, foundation distress, and vertical additions.
Publication Source: Ibrahim Metwally, PhD, PE