14 March 2021

Learning From Bridge Failures – Challenges And Opportunities

Alok Bhowmick
Managing Director,
B&S Engineering Consultants Pvt. Ltd

 

Introduction

Bridges are important. It is hard to imagine a civilization without bridges. They are essential for growth and development of human society. Bridges cannot be seen merely as a structural object to cross an obstacle or a stream. They are linkages connecting people and communities. They reveal something about the creativity of Civil Engineers/Structural Engineers at the time of creation. They even speak about our identity. Even today there are more than 1 billion people around the world (which is nearly 1/8th of the world population) living in poor conditions and many of them in remote areas hungry for food and connectivity. For them, a connecting bridge means a whole lot of difference in their life. It may help them in education, medical care, access to market and a lot more.

When Bridges fail, communities struggle. Development stagnates. People suffer. When a bridge failure occurs, the loss of the asset is only a small component of the total loss; it results in much greater national socio-economic consequences. The challenges that lie ahead to reduce failure risk is huge and this paper examines the circumstances and issues that contributed to a series of construction and engineering failures, to enable development of a systemic learning framework to contain and reduce design errors and potential failures and accidents.

Failures used to be rare in the past. But of late there have been a number of failures or distress in bridges and flyovers and other structures, either during construction or prematurely during service. Every major collapse is followed by intensive discussions between the authorities and Engineering fraternity. This in turn results in some changes in the codes and specifications and construction practices. However, there is no tangible improvement in safety standards in the opinion of the author and bridges continue to fail in the same manner. The story of why bridges failures are becoming more frequent is more complex than the technical details surrounding its design and construction. The problem of failures and distressed infrastructure asset is a serious one and needs to be addressed if India is to achieve its aspirations of rapid growth and improvement in the trust of lives of its people. The real cause of such failures can be attributed to deteriorating moral and ethical values, scant application of sound engineering judgment, lack of communication between designer and constructor, decision-making, economics, organization, culture, and individual and organizational hubris. To understand the real issues, one needs to examine the present situation holistically, looking into all these aspects. It is not a problem that can be resolved in a few years through the passage of a law or through a stand–alone short–term initiatives. Sustained long-term efforts are required by all stakeholders to address this complex problem of great importance affecting the society at large. This paper makes an attempt to bring awareness to the fact that welcome changes in many areas of the design-construction industry have and do come about with benefits realized as the result of catastrophic failures. The author would also like to urge that we, engineering professionals, press for change when warranted and try to extract all possible benefits from failures.

Are We Learning Lessons From Bridge Failures & Bringing Changes In Codes, Standards & Work Practices?

One of the impediments in learning lessons from failure is that the full details of many failures and outcome of the investigations are not made public. Fear of blame, lawsuits, damaged business opportunities and ruined reputations are all often cited as reasons for keeping failure cases and actual examples under the wraps, under legal non-disclosure agreements and in insurance company files. This is a global problem and not just India-centric issue, but some countries have found ways and means to at least generically share the lessons through more comprehensive failure dissemination methods and educational repositories. Structural failures are the result of human activities which, in the design and construction industry, are prescribed in part by codes, standards and industry practices. In case the investigation of a failure reveals that adherence to the practices allowed or indeed, created the cause of the failure, then it makes a good sense to critically review those codes, standards, regulations and industry practices, and if felt necessary these needs be revised. Take the example of failure of bridge over river Karamanasha in UP (NH-2). This 4-lane bridge with divided carriageway with 5 span continuous deck was constructed in the period between 2000-2003. The cantilever brackets of one of the Pier Cap failed with a bang on 28th December 2019, 16 years after construction (Fig. 1). Close inspection of the failed pier cap bracket and review of circumstances revealed that the failure occurred due to lack of adequate reinforcement in pier cap, unregulated overloading over the deck and poor maintenance of the bridge. The centre line of bearings in this bridge, carrying very high loads were placed at the edge of plate type pier with half the bearing projecting out on a cantilever bracket. Nominal reinforcement was only provided in the pier cap. The designer in defense referred to one of the clause in IRC:78 (Clause 710.8.4), which reads as under:

Fig. 1: Failure of Pier Cap Bracket of Karamanasha Bridge on NH-2, U.P [2019]

 

“In case bearings are placed centrally over the columns and the width of bearings/pedestal is located within half the depth of cap from any external face of the columns, the load from bearings will be considered to have been directly transferred to columns and the cap beam need not be designed for flexure.”

One of the lesson Learnt from this failure: To modify this clause of the referred code (which still exists!), which is liable to be misinterpreted resulting in collapse.

One form of “benefits”, which derives from bridge failures is the improvement of codes and practices. But there are many other benefits that manifests themselves in changes in practices of structural design, construction safety regulations, approval, oversight, inspection and other industry practices that follow catastrophic failures. There are plenty of literatures/books available highlighting “Case Studies” and “Lessons Learned” from failures. These information’s compiled based on past failures are quite useful provided the lessons are heeded and acted upon to prevent their recurrence.

Statistical Data On Bridge Failures – In India And Overseas

Collection of bridge failure/damage information, plays and important role in each era of development of bridge codes and specifications. The study of the failure of structures is an important activity related to infrastructural development. It involves different stages of planning, construction, maintenance and disposal. Although various levels of activities involved in a failure study yield limited output and outcome still, it helps in assessing associated risks with bridges during their construction or service phase. Thus, helps in assessing the performance of structures built in the past to improve the future practices. Code developers and specification writers take due cognizance of these statistical data to decide on the margins of safety and work safety specifications in code.

Recently several researchers analysed the failure of bridges particularly in the USA, China, Japan, Vietnam, etc. Literature on such statistical data is available for taking measures for mitigation of such failures [1]. Besides the failure statistics, case studies of major catastrophic bridge failures are also available in public domain for many of the failures in these countries. In one of the recent articles, Ian Firth, an acclaimed bridge expert and former President of IStructE looks back at the box-girder bridge collapses of 1970 and considers the applicability of the lessons learned to structural engineers even today [2]. The article gives clear indication that worldwide, engineering fraternity is not acting upon the past failure learnings to prevent their recurrences. This aspect is further dealt with in more details in Section 7 below.

Indian statistical data of failure is scarce. Though there are many articles written on individual failure of a particular bridge, there are very few researches done by collecting large amount of data to carry out the failure studies. The author could lay his hand to only a single article written by R K Garg, S Chandra & A Kumar of CRRI [1], which provides statistical data of failure of bridges, that occurred for 40 years, between 1977-2017. These data from 2,130 bridges (excluding culverts and foot bridges) were collected from various sources, including print and electronic media. Given below are the outcome of statistical data of failure in USA and in India, which gives many interesting information.

Statistical Data Of Bridge Failure In USA, During Service [3]

As a part of the FHWA sponsored research project in 2008, the Multidisciplinary Centre for Earthquake Engineering Research (MCEER) collected data of 1,254 bridge failures and presented in a manner which can help engineers to learn lessons. 85% of this data is taken from North America, 7% from East Asia while balance from other sources. Some of these findings are reproduced below for benefit of readers:

– Distribution of failed bridges by function:

Fig. 2: Distribution of Failure by Function

91% of the failures occurred in roadway bridges while only 2% occurred in Railway Bridges. Pedestrian Bridge failure reported was only 1% while Highway failure was 6% (Fig. 2).

– Distribution of failed bridges by material used:

Fig. 3: Distribution of Failure by Material Used

 

65% of the failures occurred in concrete bridges while 30% occurred in Steel Bridges. Other type of failure reported was only 5% (Fig. 3).

– Distribution of failed bridges by structure type:

Fig. 4: Distribution of Failure by Structure Type

58% of the failures occurred in Girder type bridges, 29% in through truss type of bridges and balance is on other type of bridges (Fig. 4).

– Distribution of failed bridges by age:

Age distribution of failed bridges is an important parameter for finalization of the strategy and procedure for maintenance of bridges. Fig. 5 shows the % of failed bridges in the age group of 10 years interval.

– Distribution of failed bridges by cause of failure:

On the basis of data provided between 1980 to 2012, it is observed that 47% of the bridge failure in USA is caused due to scour and floods. 15% failed due to collision with truck, ship or rail and 11% due to internal causes. The term ‘Internal causes’ here includes failure due to design error, construction error, material defect and lack of maintenance. Fig. 6 shows the % of failed bridges.

Fig. 5: Age Distribution of Failed Bridges

 

Fig. 6: % of Failed Bridges based on Cause of Failure

 

Statistical Data Of Bridge Failure In INDIA, During Service [1]

– Distribution of failed bridges by structure type:

Fig. 7 presents the details of the types of bridges during service. Bridges are constructed dominantly of RC and PSC (58% in a sample size of 622 bridges) followed by steel (including truss, plate girder, Bailey bridges and steel-RC composites) as 32%. The timber and masonry bridges are of the order of 7%, while the data for material used was not available for rest of bridges. The RC and PSC bridges may undergo highly nonlinear structural behavior causing concrete cracking, yielding of the reinforcing steel, and large deformations.

– Distribution of failed bridges component wise:

The component of the bridge, which triggered the failure, is identified and is presented in Fig. 2. The failure of the superstructures is 72%, followed by substructure (10%) and foundations (6%) of all failures. The dilapidated, as well as demolished conditions are 5% while the remaining 7% failures are of the abutment, earth retaining walls (REW), expansion joints and bearings. The failure of the foundation generally affects the pier, thus leading to progressive failure of the associated spans. However, segregation of the failure initiating component in terms of foundation or the pier might, in some failure cases, be subjective. Still, this piece of information towards identifying the affected specific component is crucial for failure analysis.

– Distribution of failed bridges in service based on cause of failure:

During service, the causes of failure of bridges are shown in Table 1. Various causes of failure of bridges are overloads, deterioration of material including ageing, natural disasters, design as well as construction aspects and human-made disasters, and the values are provided in Table 1. The dominant cause is the natural disasters of the order of 80.30%. Another dominating cause of failures is the deterioration of the material (10.10%) followed by the design and construction (4.13%). The overloading is the cause of 3.3%, and Human-Made disasters are 2.2% of all the failures of bridges in India.

It can be seen from the above that the failure of bridges against floods alone is a serious cause of failure of bridges in India, which is 51.2%. It is sometimes associated with uncontrolled sand mining. Sand mining has been a common practice in India to collect sand from the river bed for the use in civil engineering construction. Easy access available close to the bridge has made this practice more common to dig in the vicinity of the piers of the bridges. Excessive sand mining creates scouring around the piers, thus weakens the foundation and reduce resistance to lateral loads.

In the USA, the scouring has been reported to be more pronounced (19%, Fig. 6) than in India (0.8%). The failure of bridges due to seismic activities in India is of the order of 26.8% of all failures. Compared to this, the reported failure cases due to earthquake in USA is only 2% (Fig. 6). The reducing lower failure rates showcase the advancements made in earthquake safety research and practice in USA.

In India, storm-based bridge failures are 0.60% as compared to 0.40–8% in the USA. The scale of storm, which includes the impact from cyclone, hurricane, tornado or thunderstorm, has been more severe in the USA. Landslide induced collapse of bridges in India are not many (only 0.8%). The failures of bridges due to ice (snow) in India are also scanty.

The percentage of damage to bridges due to overloading has been observed as 3.3% in India. Compared to this, the failure rate in USA due to overloading is 13%, which is very high. The increasing trend of failures of the overloaded bridges is alarming in the USA. Though in India, the case of failure due to overloading is low, this does not give the true picture since overloading is rampant in India too. There is uncontrolled overloading by regular trucks, which is a serious issue affecting the long term fatigue related problems in the structure. The passage of a regular overloaded truck on the bridge may weaken the structure, but may not always lead to the instantaneous collapse of the bridge.

Statistical Data On Bridge Failure During Construction In India

During the last decade, there has been an increased expenditure on roads and bridges in India, and the same may also be considered proportionately for the new construction of bridges. The increase in financial outlay for roads and bridges is also reflected in the recent activities of new construction. Therefore, more cases of failure during the construction stage within the last 5 to 10 years are recorded. New-generation bridge construction are complex and delicate. Precast segmental technology is rampantly used currently. Many designers, contractors involved in such construction activities are first timers in segmental technology with little or no hands-on experience. This has resulted in a number of recent failures during construction stage. Construction stage failure statistical data are hardly gettable since many failures are not reported at all. Report of 123 such failures were analyzed in [1], and cause of failure is as given in Table 2 below:

The collapse of scaffolding supporting the formwork has been the dominating reason, with 34.4% of cases. The failures of scaffolding are due to weak temporary supports that might not have been designed to withstand the expected loads coming during the placing of concrete and its hardening. There have also been some cases of failure of scaffolding triggered after impact from vehicles plying in a close nearby traffic lane, suggesting the insufficient implementation of safety features around the new construction despite the prevalence of regulatory norms.

Statistical Data On Bridge Failures In China [4]

Economic boom has sped up urbanization over the past four decades in China. Urbanization has led to a continuous increase in demand for urban infrastructures, including bridges. Fig. 9 summarizes the causes of the 418 reported bridge collapses during the 10-year period between 2009 and 2019 in China. As shown in Fig. 9a, the causes of bridge failures can be summarized into six types: construction, flooding, scouring, collision, overload, design defects and earthquake, and wind or fire. Construction (28.7%), flooding or scouring (21.3%), and collision (18.7%) are the three main causes of bridge failure, which is in accordance with former research statistics. In addition, overload (9.1%) is one of the most important causes of bridge accidents, which is more serious than design defects (8.6%). Accumulated damages by earthquake and other hazards impose negative effect on bridge structure and lead to failures, accounting for 6.4%.

The above six failure causes can be further classified into two major categories: natural factors and anthropic factors (Fig. 9b). The proportion of failures caused by anthropic factors (69.6%) is much greater than that by natural factors (30.4%). It can be concluded that the management issues related to construction, design, maintenance and supervision are the key causes of these bridge collapses.

Fig. 10 illustrates the number of bridge collapses both in the service and in the construction stage. As shown in Fig. 10, the number of bridge collapses increased annually. Moreover, it can be seen that construction stage failures are a good proportion of total failure in China. The author is of the view that situation in India is no different. Lack of statistical data the figures cannot be presented. Strong supervision and effective quality control management are considered important for project construction.

Fig. 10: Component Wise Number of Bridges Failed in Service

Some Major Failure Case Studies In India

– Mandovi Bridge Collapse (1987)

The Mandovi Bridge in Goa collapsed (Fig. 11) in July 1986, within 15 years of its opening to public. The main reason for failure was determined to be corrosion of the pre-stressed cable that attached the precast concrete segments to the piers. Poor grouting of prestressing duct and poor maintenance of the bridge further helped in the collapse. The investigations carried out by judicial committee headed by justice Rege showed that the bridge was either not maintained/repaired for a long time or were left unattended till the collapse. The grouted prestressing cables were passing through the deck slab at the top of the pier which was the prevalent practice at that time and later prohibited in Indian codes. The collapse of one span pulled down the adjacent span as the same was connected through deck slab. Problems with corrosion due to poor grouting brought the challenges associated with proper grouting to the forefront. One of the most critical properties for a post-tensioning grout is bleed resistance. Large amounts of bleed water are common with many grouts used in standard practice. After evaporation of the bleed water, large voids may be left exposing the strand to corrosive agents. Post collapse of this bridge, there has been significant improvement in the codes and standards. A special publication IRC:SP:33 with supplemental measures for durable design was introduced by IRC for major bridges. Details of the failure from practitioners perspective is given in a technical paper which can be referred for more information [Reference 5].

Fig. 11: Mandovi Bridge in Goa, which Collapsed in 1986

 

- Collapse of Under-Construction Kota Cable Stayed Bridge, Rajasthan (2009)

Under Construction Bridge across river Chambal on Kota bypass (Fig.12) in December 2009 was most incredible and bizarre failure during construction world over, which claimed 48 lives. As reported in media during the free cantilever cast in situ construction of the cable stay bridge, cantilever decking started drooping and simultaneously the pylon started tilting towards the river. The form traveller was seen to sag towards downstream side. The pylon and cantilever arm continued to sag till form traveller hit the ground. The back span which was providing counter-weight for free cantilever construction was catapulted 100 m away from its original position. A high-level probe has identified non-compliance of construction sequence prepared by the project designer as one of the main reason behind the collapse.

Fig. 12: Kota Cable Stayed Bridge, Rajasthan, which Collapsed in 2009

- Collapse of Ultadanga Flyover, Kolkata (2013)

60 m long curved steel composite, simply supported deck of ultadanga flyover, connecting VIP road to EM Bypass toppled early morning at 4 AM on 3rd March 2013, into keshtopur canal below, when a single truck was on top of the deck. It is understood that the designed bearings were misplaced in their layout leading to toppling of the span during traffic, if so the construction management is also equally responsible for not visualising the scenario of accident by wrong positioning of bearings. Further, the wisdom of providing a simply supported span in such a sharp curvature is also questionable. Such curved deck should generally be provided with continuous deck. Fig. 13 shows the toppled deck.

Fig. 13: Ultadanga Flyover Kolkata – Toppled Curved Span

– Under-Construction Curved Flyover Collapse, Surat (2014)

3 labourers were killed and 6 others injured when a portion of an under-construction flyover at Surat collapsed on 10th June 2014 in morning hours. The curved span was with a sharp radius of curvature and the span was designed as straight span with the bearings layout to suit straight span as reported in newspaper (Fig. 14). Due to the facts of the case as reported in the media, the bridge failure in question belongs to the category of accidents caused by an oversight arising out of inexperience of the designer, by neglecting to perform important calculations, i.e. in the widest sense by calculation errors. The fact that this blunder could not be detected by the proof checker, review consultant of the project management consultant and also by the contractor executing the work at site reflects a systemic failure of the entire safety mechanism in the project.

Fig. 14: Curved Flyover Collapse at Surat

– Collapse of Under-Construction Vivekananda Flyover, Kolkata (2016)

A segment of an under-construction flyover in Kolkata collapsed suddenly on 31st March 2016, causing casualty of 26 people and injuring more than 80 people severely (see Fig. 15). Investigation by expert committee set up by state government revealed that the design of the flyover was faulty. The report also points out at the lack of use of proper construction material, faulty design approval and wrongful project execution of the authority. Details of the failure from practitioners perspective is given in a technical paper which can be referred [Reference 6].

- Recent Failures of Under-Construction Precast Segmental Bridges

Spanning over last two years, a number of structural failures in precast segmental bridges and flyovers have come to limelight. Interestingly many of these bridge failures are of similar nature and happened during the construction stage. Table 3 below gives the information’s about seven such cases of failure/collapse. Specific details of the project and stakeholders are not disclosed purposefully, considering sensitivity of the issue:

Fig. 15: Vivekananda Flyover collapse at Kolkata

Unfortunately industry is not responding to these failures with the seriousness with which these are to be handled. Reactions are mostly knee-jerk in such failures and taking advantage of the limited “Institutional Memory”, things go as usual after a time gap. The author is of the view that there is need to take serious lessons from such failures institutionally. We must collectively brainstorm, to incorporate modifications into our codes, standards, construction practices, technical specifications to prevent recurrence of such mishaps in future situations.

Public pays a high cost when our structures fail. Society expects Civil & Structural Engineers to build safe structures and therefore it is expected that we learn from our past mistakes and tend not to repeat them.

Structural engineers are under huge pressure from clients, contractors and owners to perform quickly and cheaply, potentially at the risk of quality and safety. My appeal to all Structural Engineers is that they must not yield under this pressure, and compromise on quality of work.

Growing Need For Promotion Of Forensic Structural Engineering As A Separate Profile

Since decades, structural engineers have been educated to design new structures. However the art and science of assessing the structural capacity of a distressed structure is not a subject taught in academic institutions and structural engineers only learn this in the profession based on experience. Structures are often not built as they exist and as they should be, which may result in malfunctioning, insufficient structural safety, collapse. The root cause of the problem has to be determined as quickly as possible in such situations, in order to eliminate the risk or inconvenience for the users. To this aim experienced engineers are required, who are able to come to a quick assessment based on past experience and reliable judgement.

In the past, problems with structures were mostly incidental, but nowadays structures are becoming more and more complex in design and execution, requiring high skill. New tendencies are observed, like aging of structures and their consequences, the use of software by structural engineers without understanding its background, and changes of the function of a structure during service life. There is a growing need for another profile in structural engineering: the forensic structural engineer. Expectations from this profile of Engineers are as follows:

– Should be able to judge upon deficiencies in structures, their cause and the treatment for upgrading. In order to carry out their task of finding the cause of deficiencies, damage or even partial or full collapse,
– Should dispose of profound knowledge about the real behaviour of structures. It is important to realize, that the cause of failures should not only be explained from a technical point of view, but can also be found in bad communication and lack of quality control.
- Should be able to deal with the aging of concrete structures, which asks for a lot of additional expertise in order to be able to assess the structural reliability, at the moment of investigation and during the remaining service life.
– Should be able to carry out large scale evaluations of structural safety of existing flock of structures, which are necessary due to changes in the magnitude of loads, like related to increased vehicle loads, or upgradation of codes on seismic loads.
- Education of students should be more directed to understanding structural behaviour, stimulating the ability for adequate assessment of structures.

The Way Forward On Learning From Bridge Failures

Every failure (as well as near misses), even though tragic, brings with it an opportunity to learn from it. This learning can be deep rooted and effective provided post-failure investigations are done with utmost sincerity and transparency (not with the intention to find a scapegoat but to identify real cause of failure and accountability). Learning from such events needs to be organized, catalogued and shared in a timely manner, since much of the data is perishable, and the memory of tragic events can be short. The country certainly needs better mechanisms to institutionalize such learning. Ministry of Road Transport and NHAI should take lead in facilitating the knowledge sharing experiences across governments, disciplines and professions. Professional associations like IAStructE, IIBE, CEAI and the likes can conduct webinars, workshops, journal articles sensitizing the engineering industry on these issues. The academic community across India can play a big role in documenting and analysing such learning. Journals like CE&CR can also contribute by publishing articles on failures. The learning from bridge failure should holistically cover any/all of the following aspects of bridge engineering:

– Identifying the need for review of design codes, standards and method of analysis, design, detailing for bridges to avoid recurrence of failures.
– Identifying the need to review the process of selection of materials, construction methods, erection methods presently practiced from safety considerations.
– Identifying the lacuna in the process of review of design and construction methods, which practiced in general and which is presently unable to filter the root causes of failure.
– Identifying the problem areas in current standard contract agreements which promotes sloppy construction and lousy designs.

It is not out of place to mention that Structural Engineers are still learning from two major structural failures happened 50 years ago. 15th October 2020 marks 50 years since one of Australia’s worst accidents. 35 people were killed when the West Gate Bridge in Melbourne collapsed during construction. The tragedy came just a few months after a similar accident in Milford Haven, South Wales, when the Cleddau Bridge also collapsed during construction, killing four people. Not long after another tragedy occurred. In November 1971 a steel box-girder bridge across the River Rhine near Koblenz in Germany collapsed killing 12 people.

The British government responded by setting up the Merrison Committee of Inquiry, with Dr A W Merrison, Vice Chancellor, University of Bristol as Chairman. It was tasked with investigating the design and construction methods of box-girder bridges. It was also asked to make recommendations for change. The committee was made up of some of Britain’s most respected civil and structural engineers. The report submitted in 1973 by this committee set out radically new design and workmanship rules for bridges. As a result, the Merrison committee recommended four key procedures to improve the safety of bridge design and construction:

- An independent check of the engineer’s permanent design
– An independent check of the contractor’s method of erection and temporary works design
– Clear allocation of responsibility between the engineer and the contractor
– Provision by both the engineer and the contractor of sufficient adequately qualified supervisory staff on site.

The report remain essential reading for bridge engineers [2]. While the technical lessons have been incorporated into modern codes of practice, leading to safer designs today, the procedural lessons covered in the report are still every bit as relevant.

When presenting the committee’s conclusions, the chairman’s noting is worth sharing and I wish to close this paper with his quote, which is reproduced below:

“No amount of writing of design codes and writing of contracts can in the end be guaranteed to prevent the results of stupidity, carelessness or incompetence. But one can do a great deal to discourage these vices and that must be done.”

Conclusion

a). Bridge failures are one of the worst infrastructure problems facing the World. In order to prevent or minimize these kinds of failures, an efficient and complete database of bridges and their latest conditions must be created.

b). Designers and Engineers are human and they can occasionally make mistakes which, sometimes get caught well before any mishap occurs, but in other times, this can led to failure. Generations of Engineers have studied and learned from these failures and there is no telling how many disasters had been avoided by learning from such failures.

c). It is extremely important to make the failure investigation reports public. This not only instils confidence of the society on the regulatory authority responsible for the infrastructure asset, but also gives a signal to erring contractors, consultants and clients representatives that bridge design and construction is a serious business and there is no scope for lackadaisical approach in this business.

References

1. “Analysis of bridge failures in India from 1977 to 2017” by Rajeev Kumar Garg , Satish Chandra & Aman Kumar; Structure and Infrastructure Engineering Maintenance, Management, Life-Cycle Design and Performance
2. “The Box Girder failures 50 years on – lest we forget” by Ian Firth in Viewpoint, a magazine of IStructE, published in October 2020.
3. “A Study of U.S. Bridge Failures (1980-2012)” by George C. Lee, Satish B Mohan, Chao Huang and Bastam N. Fard. – A Technical Report of MCEER-13-0008, June 15, 2013.
4. “Lessons Learnt from Bridge Collapse: A View of Sustainable Management”; by Ji-Shuang Tan, Khalid Elbaz, Zhi-Feng Wang, Jack Shui Shen, and Jun Chen;
5. “Recommissioning of Mandovi Bridge, Panaji, Goa” by S A Reddi; The Bridge & Structural Engineer, Vol. 44, Number 4, December 2014.
6. “COLLAPSE OF KOLKATA FLYOVER - PRACTITIONER’S PERSPECTIVE”, by N Prabhakar and Subramanian Narayanan; The Bridge & Structural Engineer, Vol. 47, Number 1, March 2017.