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Surfside condominium collapse – Kondominium Surfside runtuh

Surfside condominium collapse – Kondominium Surfside runtuh

Surfside condominium collapse photo from Miami-Dade Fire Rescue 1.jpg

This image shows the aftermath of the Surfside condominium building collapse which occurred on June 24, 2021. It shows the rubble that resulted from the collapse, and also clearly shows the standing portion of the building.

 

On Thursday, June 24, 2021, at approximately 1:25 a.m. EDT, Champlain Towers South, a 12-story beachfront condominium in the Miami suburb of Surfside, Florida, United States, partially collapsed. As of July 22, 2021, a total of 98 people are confirmed dead, all of whom have been identified. One 15-year-old was rescued from the rubble but his mother was fatally injured, dying shortly after arrival at the hospital. Eleven others were injured. Approximately 35 were rescued the same day from the uncollapsed portion of the building, which was demolished 11 days later. On July 7, authorities announced the transition from rescue to recovery. The search for victims officially ended on July 23, 2021.

The main contributing factor under investigation is long-term degradation of reinforced concrete structural support in the underground parking garage, due to water penetration and corrosion of the reinforcing steel. The issues had been reported in 2018 and noted as “much worse” in April 2021. A $15 million program of remedial works had been approved before the collapse, although no main structural work had been undertaken. Other factors include land subsidence, insufficient reinforcing steel seen in the debris, and corruption during construction.
The Surfside collapse is tied with the Knickerbocker Theatre collapse as the third-deadliest structural engineering failure in United States history, behind the Hyatt Regency walkway collapse and the collapse of Pemberton Mill.

 

Background

https://upload.wikimedia.org/wikipedia/commons/8/82/Champlain_Towers_South_%28Surfside%2C_Miami%2C_FL%29.jpg
Champlain Towers South before the collapse as shown in 2015

 

The residential condominium building, Champlain Towers South, was located at 8777 Collins Avenue (Florida State Road A1A) in the town of Surfside, just north of Miami Beach, Florida. It was built in 1981 by a group of developers, Champlain Towers South Associates, led by the Canadian property developer Nathan Reiber.

Champlain Towers South was part of a three-building complex along with Champlain Towers North (built at the same time), and Champlain Towers East (built between the North and South buildings in 1994). All three were L-shaped structures with 12 stories, but as of 2021, the South building contained the most units at 136 including a rooftop penthouse, varying in size from 1,200 to 4,500 sq ft (110 to 420 m2) and from one to four bedrooms. The penthouse was a controversial part of Champlain Towers South’s design, as an exemption was needed to exceed Surfside’s height limit.

William M. Friedman & Associates Architects, Inc., was the architect for the project’s 1979 contract drawings. Breiterman Jurado & Associates, consulting engineers, were responsible for engineering aspects and the 1979 contract drawings, with Breiterman and associates covering structural items and Jurado and associates covering electrical and mechanical. Nattel Construction, Inc., of Miami Beach and owned by Reiber, was the general contractor for the construction of all three buildings.

The project was the first new construction in Surfside following a moratorium on new development imposed by Miami-Dade County due to water and sewer infrastructure problems in Surfside during the 1970s. In 1979, developers paid the city US$200,000 (equivalent to $713,000 in 2020) to fund the replacement of the sewer system and secure approval for the construction of the condos.

Collapse

video icon Video shows South Florida building collapse, by Fox 13 Tampa Bay

https://www.youtube.com/watch?v=7KNwMSuwQ8w

 

The Champlain Towers South building suddenly suffered a partial pancake collapse at about 1:25 a.m. EDT on June 24, 2021, lasting less than 12 seconds. Surveillance video footage indicates that a large north-central section of the building abruptly collapsed first. This isolated and destabilized part of the northeast corner of the building, which also collapsed approximately nine seconds later. Of the 136 units in the building, at least half were destroyed.

 

Possible causes

In 2018, an inspection performed by the engineering firm Morabito Consultants showed a “major error” in the construction of the pool deck, whereby the waterproofing layer was not sloped. Water that collected on the waterproofing remained until it could evaporate. Over the years, the concrete slabs below the pool deck had been severely damaged by this water. The report noted the waterproofing below the pool deck was beyond its useful life and needed to be completely removed and replaced. The firm wrote that “failure to replace waterproofing in the near future will cause the extent of the concrete deterioration to expand exponentially”, and that the repair would be “extremely expensive”. The ceiling slabs of the parking garage, which sat below the pool deck, showed several sizable hairline cracks and cases of exposed rebar from spalling. In October 2020, initial repairs around the pool were unable to be completed because (according to engineers) the deterioration had penetrated so deeply that repairs would have risked destabilizing that area. On April 9, 2021, a letter to residents had outlined a $15-million remedial-works program, noting that concrete deterioration was accelerating and had become “much worse” since the 2018 report. Although the roof repairs pursuant to the consultant’s report were underway at the time of the collapse, remedial concrete works had not yet begun.
According to Surfside town commissioner Eliana Salzhauer, at the time of the disaster, the building had been undergoing inspection for its 40-year recertification, which typically takes one year to complete. Morabito Consultants, the engineering firm who performed the 2018 inspection, were retained by the condominium association to perform the inspection for the condominium’s 40-year recertification.

In addition to water from the defectively constructed pool deck, a maintenance manager had reported a possible excessive ingress of salt water, which can cause more aggressive spalling. On June 28, 2021, images were published by the Miami Herald from an anonymous pool contractor, who claimed that they showed portions of the pool equipment room, located under the pool on the south side of the underground garage, as they appeared just 36 hours before the collapse. According to the contractor, the images showed standing water, cracking concrete, and severely corroded rebar under the pool. On June 30, WLS-TV in Chicago publicized a bystander’s video of water pouring into the parking garage from above near its entrance, and apparent concrete rubble lying on the floor, apparently taken at 1:18 a.m., seven minutes before the north-central portion of the building collapsed.

 

On July 3, the New York Times reported that investigators had found less rebar than specified in the building’s construction plans in its footing neck and starter columns. The report cautioned that some may have been dislodged in the collapse, and that reduction of rebar alone would not necessarily cause failure because steel requirements can change during the construction process, and designs often specify more than is strictly needed as a safety precaution. Construction contractors using less rebar than required is a very common cause of structural failure. There is no way to inspect that the proper amount of rebar has been used in reinforced concrete except during construction or with extremely expensive and destructive replacement. There is some evidence that proper inspections were not performed during and after construction.

Distinct from possible construction defects, an analysis of European Remote-Sensing Satellite data by Florida International University indicates that the building had been sinking during the 1990s at a significant rate of about two millimeters (0.079 in) per year. While 97 percent of Miami Beach had been stable, 1,555 of 18,949 points in Miami Beach had been sinking, at a rate of less than one millimeter (0.039 in) per year. A building collapse due to sinking is only likely if parts are sinking at different rates, creating tensions that weaken the structure, known as differential settlement. The researchers noted that other overbuilt areas were sinking at a significantly faster rate, such as on the artificial islands in Biscayne Bay – up to 3.8 millimeters (0.15 in) per year.

On June 27, 2021, the Miami Herald reported on the consensus of six engineering experts it interviewed. Based on publicly available evidence, the experts believed that a structural column or concrete slab beneath the pool deck likely gave way, causing the deck to collapse into the garage below. This formed a crater beneath the bulky midsection of the tower, which then caved in. This is a type of progressive collapse, in which one structural part gives way, destabilizing and removing support from other parts, which in turn collapse and rapidly remove structural support. Evidence includes the report that moments before the building collapsed, a resident of a fourth-floor unit called her husband to say that a crater had appeared in the pool deck. She went missing in the collapse. A surviving resident also stated that part of the pool deck and street-level parking area had collapsed into the parking garage minutes before the collapse.

 

On June 28, 2021, The New York Times reported that the secretary of the resident-led association that managed Champlain Towers South contacted the town building department in early 2019 due to resident concerns that their building’s structural integrity was affected by the construction next door at the Eighty Seven Park condo development. The project broke ground in early 2016 and was completed in late 2019. No known engineering records suggest a connection between Eighty Seven Park construction and any damage at Champlain Towers.

Corruption during construction has been cited by multiple local media sources as a potential contributing cause of the collapse.

Terjemahan bebas:

 

Pada hari Kamis, 24 Juni 2021, sekitar pukul 01:25 EDT, Champlain Towers South, sebuah kondominium tepi pantai 12 lantai di pinggiran Miami, Surfside, Florida, Amerika Serikat, sebagian runtuh. Hingga 22 Juli 2021, total 98 orang dipastikan tewas, semuanya telah teridentifikasi. Seorang anak berusia 15 tahun diselamatkan dari puing-puing tetapi ibunya terluka parah, meninggal tak lama setelah tiba di rumah sakit. Sebelas orang lainnya terluka. Sekitar 35 orang diselamatkan pada hari yang sama dari bagian bangunan yang belum runtuh, yang dihancurkan 11 hari kemudian. Pada 7 Juli, pihak berwenang mengumumkan transisi dari penyelamatan ke pemulihan. Pencarian korban resmi berakhir pada 23 Juli 2021.

Faktor kontribusi utama yang diselidiki adalah degradasi jangka panjang dari dukungan struktural beton bertulang di garasi parkir bawah tanah, karena penetrasi air dan korosi baja tulangan. Masalah tersebut telah dilaporkan pada 2018 dan dicatat sebagai “jauh lebih buruk” pada April 2021. Program perbaikan senilai $15 juta telah disetujui sebelum keruntuhan, meskipun tidak ada pekerjaan struktural utama yang dilakukan. Faktor lain termasuk penurunan tanah, baja tulangan yang tidak mencukupi terlihat di puing-puing, dan kerusakan selama konstruksi.
Runtuhnya Surfside terkait dengan runtuhnya Knickerbocker Theatre sebagai kegagalan rekayasa struktural paling mematikan ketiga dalam sejarah Amerika Serikat, di belakang runtuhnya jalan setapak Hyatt Regency dan runtuhnya Pemberton Mill.

 

Latar belakang

 

https://upload.wikimedia.org/wikipedia/commons/8/82/Champlain_Towers_South_%28Surfside%2C_Miami%2C_FL%29.jpg

Champlain Towers Selatan sebelum runtuh seperti yang ditunjukkan pada tahun 2015

 

Bangunan kondominium tempat tinggal, Champlain Towers South, terletak di 8777 Collins Avenue (Florida State Road A1A) di kota Surfside, tepat di utara Miami Beach, Florida.  Dibangun pada tahun 1981 oleh sekelompok pengembang, Champlain Towers South Associates, dipimpin oleh pengembang properti Kanada Nathan Reiber.

Champlain Towers South adalah bagian dari kompleks tiga bangunan bersama dengan Champlain Towers North (dibangun pada waktu yang sama), dan Champlain Towers East (dibangun antara bangunan Utara dan Selatan pada tahun 1994). Ketiganya adalah struktur berbentuk L dengan 12 lantai, tetapi pada tahun 2021, bangunan Selatan berisi unit terbanyak di 136 termasuk penthouse atap, dengan ukuran bervariasi dari 1.200 hingga 4.500 kaki persegi (110 hingga 420 m2) dan dari satu sampai empat kamar tidur. Penthouse adalah bagian kontroversial dari desain Champlain Towers South, karena pengecualian diperlukan untuk melebihi batas ketinggian Surfside.

William M. Friedman & Associates Architects, Inc., adalah arsitek untuk gambar kontrak proyek 1979. Breiterman Jurado & Associates, insinyur konsultan, bertanggung jawab untuk aspek-aspek teknik dan gambar kontrak 1979, dengan Breiterman dan rekan-rekan meliputi item struktural dan Jurado dan rekan-rekan meliputi listrik dan mekanik. Nattel Construction, Inc., dari Miami Beach dan dimiliki oleh Reiber, adalah kontraktor umum untuk pembangunan ketiga bangunan tersebut.

Proyek ini merupakan konstruksi baru pertama di Surfside menyusul moratorium pembangunan baru yang diberlakukan oleh Miami-Dade County karena masalah infrastruktur air dan saluran pembuangan di Surfside selama tahun 1970-an. Pada tahun 1979, pengembang membayar pemerintah kota sebesar US$200.000 (setara dengan $713.000 pada tahun 2020) untuk mendanai penggantian sistem saluran pembuangan dan mendapatkan persetujuan untuk pembangunan kondominium.

Runtuh

 

ikon video Video menunjukkan runtuhnya bangunan Florida Selatan, oleh Fox 13 Tampa Bay

https://www.youtube.com/watch?v=7KNwMSuwQ8w

 

 

Gedung Champlain Towers South tiba-tiba mengalami keruntuhan sebagian panekuk sekitar pukul 01.25 EDT pada 24 Juni 2021, berlangsung kurang dari 12 detik. Rekaman video pengawasan menunjukkan bahwa bagian utara-tengah bangunan yang besar tiba-tiba runtuh terlebih dahulu. Bagian sudut timur laut bangunan yang terisolasi dan tidak stabil ini, yang juga runtuh kira-kira sembilan detik kemudian. Dari 136 unit yang ada di gedung tersebut, setidaknya setengahnya hancur.

 

Kemungkinan penyebab

Pada tahun 2018, inspeksi yang dilakukan oleh perusahaan teknik Morabito Consultants menunjukkan “kesalahan besar” dalam konstruksi dek kolam, di mana lapisan kedap air tidak miring. Air yang terkumpul pada waterproofing tetap ada sampai bisa menguap. Selama bertahun-tahun, pelat beton di bawah dek kolam telah rusak parah oleh air ini. Laporan tersebut mencatat bahwa lapisan kedap air di bawah dek kolam telah melampaui masa pakainya dan perlu dilepas dan diganti sepenuhnya. Perusahaan itu menulis bahwa “kegagalan untuk mengganti waterproofing dalam waktu dekat akan menyebabkan tingkat kerusakan beton meluas secara eksponensial”, dan bahwa perbaikannya akan “sangat mahal”. Pelat langit-langit garasi parkir, yang berada di bawah dek kolam renang, menunjukkan beberapa retakan garis rambut yang cukup besar dan kasus-kasus tulangan yang terbuka karena terkelupas. Pada bulan Oktober 2020, perbaikan awal di sekitar kolam tidak dapat diselesaikan karena (menurut teknisi) kerusakan telah menembus begitu dalam sehingga perbaikan berisiko mengganggu kestabilan area tersebut. Pada tanggal 9 April 2021, sebuah surat kepada penduduk telah menguraikan program perbaikan senilai $15 juta, mencatat bahwa kerusakan beton semakin cepat dan menjadi “jauh lebih buruk” sejak laporan 2018. Meskipun perbaikan atap berdasarkan laporan konsultan sedang berlangsung pada saat keruntuhan, pekerjaan perbaikan beton belum dimulai.
Menurut komisaris kota Surfside Eliana Salzhauer, pada saat bencana, bangunan tersebut telah menjalani pemeriksaan untuk sertifikasi ulang 40 tahun, yang biasanya membutuhkan waktu satu tahun untuk diselesaikan. Konsultan Morabito, perusahaan teknik yang melakukan inspeksi 2018, ditahan oleh asosiasi kondominium untuk melakukan inspeksi sertifikasi ulang kondominium selama 40 tahun.

Selain air dari dek kolam yang dibangun dengan cacat, seorang manajer pemeliharaan telah melaporkan kemungkinan masuknya air asin yang berlebihan, yang dapat menyebabkan spalling yang lebih agresif. Pada 28 Juni 2021, gambar diterbitkan oleh Miami Herald dari kontraktor kolam renang anonim, yang mengklaim bahwa mereka menunjukkan bagian dari ruang peralatan kolam renang, yang terletak di bawah kolam di sisi selatan garasi bawah tanah, karena muncul hanya 36 jam. sebelum keruntuhan. Menurut kontraktor, gambar-gambar itu menunjukkan genangan air, beton retak, dan tulangan yang terkorosi parah di bawah kolam. Pada tanggal 30 Juni, WLS-TV di Chicago memublikasikan video air yang mengalir ke garasi parkir dari atas dekat pintu masuknya, dan puing-puing beton yang tampak tergeletak di lantai, tampaknya diambil pada pukul 1:18, tujuh menit sebelum utara-tengah. sebagian bangunan runtuh.

Pada 28 Juni 2021, The New York Times melaporkan bahwa sekretaris asosiasi yang dipimpin penduduk yang mengelola Champlain Towers South menghubungi departemen pembangunan kota pada awal 2019 karena kekhawatiran penduduk bahwa integritas struktural bangunan mereka terpengaruh oleh konstruksi di sebelahnya. pembangunan kondominium Eighty Seven Park. Proyek ini dimulai pada awal 2016 dan selesai pada akhir 2019. Tidak ada catatan teknik yang menunjukkan hubungan antara konstruksi Eighty Seven Park dan kerusakan di Champlain Towers.

Korupsi selama konstruksi telah dikutip oleh berbagai sumber media lokal sebagai penyebab potensial keruntuhan.

 

Pelajaran dari Pembangunan Bendungan | Dam construction Lesson Learnt | ‘design errors’ caused Ituango Colombia dam collapse?

Pelajaran dari Pembangunan Bendungan | Dam construction Lesson Learnt | ‘Substandard construction’ caused Laos dam collapse

 

Pelajaran Konstruksi dari Peristiwa Bangunan Roboh di Kenya | Five reasons why buildings collapse

Risks in Fertilizer Manufacturing Plant – Risiko dalam Pabrik Pupuk

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