Analysis Of Structural Collapse Case Studies By Means Of Forensic Engineering

Introduction to forensic engineering

Forensic engineering may be stated as the application of engineering principles and methodologies for the purpose of court of law. Consequently, it involves the research of substances that are to be used for making a structure which fails to stay as long as it was expected, resulting in injury, and damage to belongings and monetary loss. The failing of the same may result in taking the legal step, i. e. , criminal or civil. This subject also offers with the recollecting the information about the methods and procedures done which led to the accident of cars or in equipment.

Basically, the primary motive of the forensic engineer is to discover the cause or causes which led to the failure, or to assist the courtroom in finding the records associated with the accident. It additionally involves the research of the highbrow belongings claims, specifically patents. In the forensic engineering investigation, the process of collecting information about the structure, substances used, components, products is done which includes inspections, measurements, or performing experiments.

The responsibilities a forensic engineer is having are as follows:

1. 1) Investigating the crime scene to find the cause of the structural collapse
2. 2) Making reports on the basis of the evidences found at the crime scene which led to the damage
3. 3) Giving opinions and testimony in the court proceeding as an expert witness
4. 4) Preparing a ideal structure which will be safe from any damage
5. 5) Connect with clients and other professionals In this assignment, there will be some information about structural collapse and human injury and case examples for same.

Structural collapse

Before discussing about structural collapse, there is a term structural integrity. It is an aspect in engineering which deals with the ability of the structure to take load of a designed structure without getting damaged. To create a structure with its integrity, the material used should be examined on the basis of toughness, strength, weight, hardness and add the material accordingly so the structure will be there for long time.

Structural collapse involves the loss of the capacity to take the load of the structure which can lead to the formation of deformation and in extreme cases, can result in catastrophic event.

Structural collapse can happen by many reasons, these are:

1. 1) The first will be the poor strength and toughness of the structure to support the load. This can happen due to its size, shape or choice of the material.
2. 2) The second can be from the enervation or corrosion of the material used for the construction of the structure which led to the instability of the same.
3. 3) The third can be caused by errors made during the construction of the structure which involves incorrect sizing, improper use of materials, or inferior workmanship.
4. 4) The fourth can be the use of the defective materials.
5. 5) The fifth and the last reason can be the carelessness for considering the minor problems. These may be minor at first, but further ignorance can result in the catastrophic events. This also includes not making structures resilient to the natural disasters.

Therefore proper knowledge of materials which are to be used for constructing the structure can somewhat helps in maintaining the structure for a longer time preventing from causing any catastrophic event.

Case 1

The Royal Palm Hotel consisted of twin 12-storey concrete special moment resisting frames. It was at Tumon Beach, Guam. The building was designed in 1990 according to the requirements of the 1988 Uniform Building Code. Guam is strike frequently to sturdy earthquakes and typhoons. The island was designated as Uniform codification Zone3, and additionally had wind speeds of a hundred and forty miles per hour. Structural design was made by a Civil Engineer, authorized in each island and California. The engineer of record for the project is also considered as the Special Inspector of record. Guam is a U. S. territory. Licensing laws on Guam is nearly same to those in California, with at a civil license and structural title. At the time of the collapse, the structural engineer failed to possess structural title authority.

Construction of the building was completed in July, 1993. On August eight, 1993 a powerful earthquake cask the island, causing partial collapse of the structure, which decided to be a complete loss. No fatalities occurred however there have been some injuries.

A protracted proceeding ensued following the collapse and extensive structural investigations were performed by variety of U. S. experts. Extensive style and construction flaws were found within the structure. These included:

• The analytical model accustomed design the structure had varied errors, together with many columns that were revolved 90o from their actual orientation
• Extra confinement hoops required around column splices were not given on the drawings
• Masonry infill walls created short column conditions throughout the structure
• Strong-column weak beam criteria were not complied withIt was additionally determined that the contractor did not follow the structural details on thedrawings. Specifically, 2 important flaws were found:
• The contractor substituted “U” shaped stirrups for the closed ties required within the joints of the special moment resisting frame.
• The contractor omitted closed hoops in several joints of the concrete special moment frame.

Special examination reports, signed by the engineer of record, and indicated that the improperly made joints had been inspected by the engineer, which he approved of the location of reinforcing steel. Further, correspondence and notes on drawings indicate that as a result of the seismic style forces for the structure were less than the wind forces, compliance with the description necessities for special moment frames, tho' fascinating, was notessential.

Two primary styles of failure – shear failure of joints within the special concrete frame and shear failure and compressive crushing of gravity columns occurred at one in all the 2 structure’s second story. This resulted in partial collapse of the structure, and eventual demolition of each structure.

In trial, the jury ultimately found the contractor to blame for the collapse, but not before the engineer of record omitted culpability and settled out of the proceedings, giving up his insurance cowl within the process. Although the contractor was ultimately found to be financially to blame for the collapse, for failure to construct the building as shown on the drawings, there's no question that the look had several errors and that intensive injury, possibly including collapse, might have occurred even if the structure was made as designed. Further, the structural engineer’s complicity within the incorrect construction, given that he acted as special inspector for the project is while not question. The structural engineer failed to have correct understanding of the premise for earthquake resistant requirements within the codification and failed to act providentially either in planning the building or acting as its special inspector. Ultimately this resulted within the total loss of a $70 million edifice, just weeks after its completion and total monetary losses that quite doubled the building’s construction price.

Case 2

On 15th November 2010, around 8. 15 PM, 5 and above storey building near Lalita Park, Laxmi Nagar, East Delhi, collapsed, killing 71 people & injuring 65. Over 60 families, mostly labourers have been living within the restricted area of the 20-year-old building. Little or inadequate damp proofing measures had been taken up with the aid of the owner/civic authority for the basement leakage. No measures, such as pumping out of water, sealing of leakage or monitoring of basis deterioration, have reportedly been taken up. The building became suspected to have weakened in the course of heavy monsoon, followed by incipient seepage into the basement, which was present till Rainey well No. 10 started flushing out water in the starting of January 2011. The Government of National Capital Territory of Delhi instituted a Commission of Inquiry to check out the reasons of the collapse of the building, examine the constructed up structures’ safety in East Delhi and recommend measures to prevent similar incidents in future.

In taking up forensic investigations of this building, some aspects of layout of the structure, construction and movements which are being done maintain the structure have been studied in detail to investigate why, when, how, and what went wrong and more importantly, what are the signs and scenarios that led to a surprise fall about. This building turned into a privately owned residential constructing under the jurisdiction of Municipal Corporation of Delhi (MCD). It began with one storey constructing in 1988, then extended to three storey in 1990 and then to five storey in 2005. Fundamental principles of constructions prescribed by BIS and NBC-2005 had been hardly ever visible accompanied. This building included complete area of plot (4. 7m x 18. 6m) with cantilever projections and floating walls on all three facets. It had basement of 3m depth and 12 columns which were located at the plot boundary, thus rendering all footing to be eccentrically loaded. The whole colony comes under Yamuna flood plain yet little or no attention was given in the seepage protective measures. The constructed height (20. 5m) was more than 4 times the plot width (4. 7m). In addition, the overhang from ground floor to full height in the Western side was almost 50% of the base width, thus making it liable to structural instability. The building had 40 odd rooms with reportedly housing greater than 200 human beings. To such building, existing building bye-laws, development control rules, land use policy and master plan etc. cannot be complied with.

An investigation from the Magistrate for the incident was ordered and under Section 304 of the Indian Penal Code, a charge of being guilty or homicide but not for murder was recorded against the building's owner, Amrit Singh. Singh tried to escape but was later captured. The authority of Delhi declared an ex-gratia of Rs 2 lakh each to the families of those killed and Rs 1 lakh to the injured.