Bangkok Building Collapse: Rescue Teams Hunt for 72 Missing Workers

[snoop1130]

 

In the heart of Bangkok's Chatuchak district, a tragic scene unfolds as rescue teams relentlessly search for 72 construction workers still missing after the catastrophic collapse of an under-construction 30-story building. The State Audit Office structure crumbled last Friday, March 28, following a severe 8.2-magnitude earthquake near Mandalay, Myanmar. The tremors were felt widely, including in Thailand’s Mae Hong Son province.

 

As of this morning, April 2, the death toll stands at 15, with eight men and seven women confirmed dead, alongside nine others suffering injuries. Despite the challenging conditions, officials remain committed to finding survivors, working tirelessly amidst the debris. The grim discovery today involved the recovery of a female worker from the building's Zone D, her body transported to the Police General Hospital’s Institute of Forensic Medicine.

 

The disaster has ignited serious concerns regarding building safety protocols in the wake of such seismic events. As efforts to locate the missing workers continue, families await word on their loved ones, with the weight of uncertainty pressing heavily.

 

 

 

This incident reverberates across the construction sector and wider community, emphasising the dire need for stringent safety measures in earthquake-prone areas. Authorities vow to persist in their search and rescue operations, although the harsh reality of the situation dampens hopes.

 

As Bangkok and the surrounding region absorb the scale of the disaster, mourning intertwines with a resolve to ensure such a tragedy does not recur. In the days ahead, the focus remains on recovery and understanding the full impact of this harrowing event, reported The Thaiger.

 

-- 2025-04-02

 

 

[mfd101]

As usual in Thailand, the 'authorities' - and Thais in general - are better at picking up the pieces after a disaster than at preventing a disaster in the first place. We all see this on the roads every day of the year.

[hotchilli]

16 hours ago, snoop1130 said:

This incident reverberates across the construction sector and wider community, emphasising the dire need for stringent safety measures in earthquake-prone areas.

Safety last Thailand, always an afterthought

[AustinRacing]

It’s only one building. It should’ve be cleared in one day. The area has more people and equipment around the perimeter than actually at the building site. Stop posting your videos online and remove the rubble pronto you fools. People are dying minute by minute. 

[couchpotato]

10 minutes ago, AustinRacing said:

It’s only one building. It should’ve be cleared in one day. The area has more people and equipment around the perimeter than actually at the building site. Stop posting your videos online and remove the rubble pronto you fools. People are dying minute by minute. 

The fool might be the AR poster who thinks 30 floors of impacted concrete and steel can be cleared in a day. You are a person that probably believes in skyhooks.

[Dr B]

Over the five days since the earthquake and collapse, there have been a huge number of comments on AN, the vast majority by people who know little or nothing about construction. Specifically these include suggestions that columns were too slender and not "earthquake proof", and that this was Table Top construction. I assume that Table Top construction is somethign done in the kitchen, which is where the people who made the comments would be better employed. I think the term they were looking for is Table Form, which is used as formwork for the underside of flat floor slabs, and has been now for many decades. Once the ground floor is cast, the table forms are set up to the required height, the reinforcement and prestressing laid out, and the concrete poured, compacted and levelled. Commonly extra cement is used to gain early strength, such as 28 day strength in 7 days. Once the first floor is stiff enough the prestressing is applied, then the second set of table forms can be set up, and the process repeated. The same with a third set, by which time the first set is no longer required and can be moved to build the fourth floor, and so on to the top.

The prestressing allows thinner slabs and less beams. This reduces the building weight, hence column sizes and foundations, and also reduces floor to ceiling heights. Leaving out beams could reduce that by 300 mm, which would be a 9 m (about 7%) saving in a 30 storey building, with significant savings in vertical construction cost. The prestressed slabs are supported vertically by the columns, at which they are very efficient. They do not take horizontal loads, whether from wind or earthquake. These are taken by the core, which is where the lifts are housed, and has three solid walls, and one wall with strengthened openings for ingress and egress, so very stiff and strong. The floor slabs easily transmit horizontal forces to the core. That is how virtually all high rise buildings work, including the 70 storey condominium in Bangkok for which I designed the foundations.

Then we come to the construction, and there as been inconsistency in the reporting from journalists who do not understand all the details of what they write. From what I have read, the overall Chinese contractor is CREC, and they are extremely large globally. They appear to have a division called CRCC, who in turn have a branch in Thailand. That branch appears to have been in JV with ITD. JVs are separate business entities with their own Boards of Directors and shareholding, so can go bankrupt without either of the main partners becoming bankrupt. I have certainly read that for CRCC Thailand this was their first high rise construction. That should not have mattered too much since ITD have a lot of experience, including their own 42 storey head office bult 30 years ago, and many others.

There was a post on AN earlier of a Google or similar translation of a press release from CRCC which made it clear that the core was to be slip formed. This is a major red flag. Slip forming is a very successful but highly technical process, in which the vertical core is poured in one continuous operation, 24/7, with the form moving very slowly, and long enough that fresh concrete is placed at the top while that coming out at the bottom is strong enough to stand and support the weight from above. For the concrete to be monolithic fresh concrete must always be placed on and vibrated into concrete which is still fluid, so this requires very careful management and control, and therefore substantial experience. It is not something learned from textbooks or in a univesity course, but by working alongsid epeole who know what they are doing. I do not know if ITD had expereince of slip forming, and if this was CRCC's first high rise building they may also not have had experience, which is a very major concern. It was also reported, without details, that the project had been hit by numerous delays. Clearly this raises the risk that these "delays" impacted the 24/7 operation of the slip forming, which cannot be stopped. I am not an expert but I would imagine that, if the process is stopped, the upper layer of concrete will not be at full strength. There is therefore probably a procedure whereby the forms have to be removed, all understrength concrete broken out, bonding agent applied, forms refixed and concreting continued with extra care on vibration at the joint. This would be a lengthy and tedious process, and likely to be cut short if persons are not familiar with slip forming. The result would be a horizontal "dry joint" in the core at each stoppage, which would have significantly reduced shear strength. This would not be apparent during construction, with virtually all loads vertical. However once complete and fully clad, and wind loads would result in high shear forces at the base, and an earthquake would lead to the piled foundations moving with the soil while the inertia of the building tries to resist, also resulting in a large shear force at the base. If there were dry joints then this force would all have to be taken by the steel, which would lead to rupture of the core walls. This would then lead to progressive collapse of the building from the bottom up, and the reason why there is no sign of the core in the rubble heap, even though it should be the strongest element of the building. I have seen the video of a few high level columns rupturing, but as the tower goes down most of the upper floors are seen to be all falling together at the same separation, showing that the main failure is from the bottom.

So that is where I believe any investigation needs to be concnetrated, particulalry on records of the slip forming, and delays and stoppages, at what levels, and what remedial measures were undertaken?

[steve187]

2 hours ago, AustinRacing said:

It’s only one building. It should’ve be cleared in one day. The area has more people and equipment around the perimeter than actually at the building site. Stop posting your videos online and remove the rubble pronto you fools. People are dying minute by minute. 

you an expert on recovery then

[couchpotato]

52 minutes ago, Dr B said:

Over the five days since the earthquake and collapse, there have been a huge number of comments on AN, the vast majority by people who know little or nothing about construction. Specifically these include suggestions that columns were too slender and not "earthquake proof", and that this was Table Top construction. I assume that Table Top construction is somethign done in the kitchen, which is where the people who made the comments would be better employed. I think the term they were looking for is Table Form, which is used as formwork for the underside of flat floor slabs, and has been now for many decades. Once the ground floor is cast, the table forms are set up to the required height, the reinforcement and prestressing laid out, and the concrete poured, compacted and levelled. Commonly extra cement is used to gain early strength, such as 28 day strength in 7 days. Once the first floor is stiff enough the prestressing is applied, then the second set of table forms can be set up, and the process repeated. The same with a third set, by which time the first set is no longer required and can be moved to build the fourth floor, and so on to the top.

The prestressing allows thinner slabs and less beams. This reduces the building weight, hence column sizes and foundations, and also reduces floor to ceiling heights. Leaving out beams could reduce that by 300 mm, which would be a 9 m (about 7%) saving in a 30 storey building, with significant savings in vertical construction cost. The prestressed slabs are supported vertically by the columns, at which they are very efficient. They do not take horizontal loads, whether from wind or earthquake. These are taken by the core, which is where the lifts are housed, and has three solid walls, and one wall with strengthened openings for ingress and egress, so very stiff and strong. The floor slabs easily transmit horizontal forces to the core. That is how virtually all high rise buildings work, including the 70 storey condominium in Bangkok for which I designed the foundations.

Then we come to the construction, and there as been inconsistency in the reporting from journalists who do not understand all the details of what they write. From what I have read, the overall Chinese contractor is CREC, and they are extremely large globally. They appear to have a division called CRCC, who in turn have a branch in Thailand. That branch appears to have been in JV with ITD. JVs are separate business entities with their own Boards of Directors and shareholding, so can go bankrupt without either of the main partners becoming bankrupt. I have certainly read that for CRCC Thailand this was their first high rise construction. That should not have mattered too much since ITD have a lot of experience, including their own 42 storey head office bult 30 years ago, and many others.

There was a post on AN earlier of a Google or similar translation of a press release from CRCC which made it clear that the core was to be slip formed. This is a major red flag. Slip forming is a very successful but highly technical process, in which the vertical core is poured in one continuous operation, 24/7, with the form moving very slowly, and long enough that fresh concrete is placed at the top while that coming out at the bottom is strong enough to stand and support the weight from above. For the concrete to be monolithic fresh concrete must always be placed on and vibrated into concrete which is still fluid, so this requires very careful management and control, and therefore substantial experience. It is not something learned from textbooks or in a univesity course, but by working alongsid epeole who know what they are doing. I do not know if ITD had expereince of slip forming, and if this was CRCC's first high rise building they may also not have had experience, which is a very major concern. It was also reported, without details, that the project had been hit by numerous delays. Clearly this raises the risk that these "delays" impacted the 24/7 operation of the slip forming, which cannot be stopped. I am not an expert but I would imagine that, if the process is stopped, the upper layer of concrete will not be at full strength. There is therefore probably a procedure whereby the forms have to be removed, all understrength concrete broken out, bonding agent applied, forms refixed and concreting continued with extra care on vibration at the joint. This would be a lengthy and tedious process, and likely to be cut short if persons are not familiar with slip forming. The result would be a horizontal "dry joint" in the core at each stoppage, which would have significantly reduced shear strength. This would not be apparent during construction, with virtually all loads vertical. However once complete and fully clad, and wind loads would result in high shear forces at the base, and an earthquake would lead to the piled foundations moving with the soil while the inertia of the building tries to resist, also resulting in a large shear force at the base. If there were dry joints then this force would all have to be taken by the steel, which would lead to rupture of the core walls. This would then lead to progressive collapse of the building from the bottom up, and the reason why there is no sign of the core in the rubble heap, even though it should be the strongest element of the building. I have seen the video of a few high level columns rupturing, but as the tower goes down most of the upper floors are seen to be all falling together at the same separation, showing that the main failure is from the bottom.

So that is where I believe any investigation needs to be concnetrated, particulalry on records of the slip forming, and delays and stoppages, at what levels, and what remedial measures were undertaken?

Thank you..most informative.