Seminar on Detailed Structural Investigation

Last week, ASEP held another seminar regarding detailed structural investigation. I am very eager to attend here but my schedule does not allow me to. Though I have substantial knowledge on the topics (see below later), attending such seminar is a must for structural engineers. I am outlining the topics and will try to typed out everything I know about them:

1. Objectives of Structural Investigation
   1. Here in the Philippines, the main scare regarding the coming of the Big One or the Magnitude 7.2 earthquake from Marikina Valley Fault line prompted all concerned building owners to check the adequacy of their structure to withstand such shaking. Not only that, some buildings were designed using the old NSCP codes. Thus, analysis of the structure using the latest Code must be implemented. Its a separate topic below.
2. Data Gathering
   1. For structural engineers, data gathering like the measurement of structural sizes of the beams and columns are very important. Also, the number of rebars installed on the structural members will be the input in the structural investigation and will be the basis of the adequacy of the building.
3. Destructive Testing Procedures
   1. Topic number 4 below is always the first priority and not the destructive testing. However, certain datas like number and sizes of rebars are difficult to determine on site thus the need for destructive testing. Again, it will depend on the significance of the investigation if destructive testing will be required. We personally do not recommend this. With this, building owners are encouraged to keep their building structural plans to make sure that datas like rebar size and columns are known.
4. Non DEstructive testing procedures
   1. This is the first major step in the investigation. Rebar scanning or detection is one type of nondestructive testing.
5. Engineering Evaluation
   1. After all datas are gathered, analysis of the building will be done and evaluation will follow.
6. Effects of fire in strength of concrete and structural fire loads
7. Target Seismic Performance LEvel
   1. This kind of topic always leads me to think about performance based analysis  which is a more technically advance topic.
8. Earthquake Parameter response spectrum and time history
   1. The NSCP has what we call design response spectrum which all structure must be designed with. Parameters like building period, distance to fault line and soil type where building rests are all required to formulate this response spectrum(graph). Time history is a more detailed analysis wherein the building will be subjected to known earthquake acceleration and investigation of the response is required. I believe that deep understanding of structural dynamics is required here.
9. NSCP
   1. The code that every structural engineers use in the Philippines to design structure to withstand earthquake.
10. Retrofitting Techniques
    1. After analysis of the structure in the investigation is finished, proper retroffiting techniques will be recommended. As a rule of thumb, structures designed prior to year 2000 has tendency to fail with the current code provision. Note that this is my personal experience only because the code used then was NSCP 1994 I believe. Please check.
11. Crack Repair
    1. Building failure is normally reflected through the occurences of cracks. However, most people are not aware, that structural engineers actually design most structural members to crack but with certain allowable size only. The idea of designing members to crack is to follow ductile failure rather than brittle failure which is indicated in the code. Again, most cracks we see in structure are non-structural. Structural engineers are required to see if cracks are structural failure in nature.
12. Alternative Strengthening of RC structures using Fiber Reinforced polymers
    1. This technology were already used before but needs further discussion since its avery popular way of retrofitting technique.
13. Retrofitting the building performance using dampers/base isolation.
    1. This technology is also very popular in Japan because they experience earthquake almost everyday.