工程师们对可能导致佛罗里达州Surfside 12层的Champlain Towers南部住宅公寓的令人震惊和致命的部分崩溃感到困惑。发生在6月24日凌晨，具有扁平平板地板的钢筋混凝土结构的故障导致尚不清楚的死亡总数。

随着急救人员在现场加强工作时，迈阿密戴德县市长丹妮拉·莱文·卡瓦（Daniella Levine Cava）在6月27日确认了9人死亡，估计有156人未被责备。她还说，将立即进行30天的审计，该审计立即在县管辖区下的所有建筑物开始，年龄在40岁及以上，或附近四年一的商标，并补充说，迈阿密戴德市的城市中的官员也将订购类似老年人的检查他们负责的建筑物。

花费了几秒钟的渐进失败被认为是结构工程师在美国建筑物中的“高度不寻常”和“闻所未闻”的特征。

“This is a highly unusual [progressive] collapse, the first being the extent of it,” says Glenn Bell, a forensic structural engineer and director of Collaborative Reporting for Safer Structures (CROSS-US), a division of the American Society of Civil Engineers' Structural Engineering Institute. The building pancaked "very quickly," adds Bell.

突然的渐进式崩溃很少见。作为一名法医工程师，贝尔说，他只参与调查一个“少数”在他的45年职业生涯中“降低到这种程度”的“少数”。

贝尔补充说，这座建筑已经站立了近40年，但经历了如此突然的渐进式崩溃，这也很奇怪，而且很少见。这种程度的灾难性渐进式崩溃通常是由于“设计和/或构造的系统性问题”造成的，这些问题通常在结构完成后不久或在建筑物完成后不久揭示。

Video courtesy The Miami-Dade Fire Rescue via Twitter

“A lot of the investigation in this case I'm sure is going to focus around" why the structure stood for 40 years and then suddenly collapsed, Bell says. Questions over changes in the beach-facing structure’s inherent strength or capacity since it was built are likely to be a focus of the investigations as well.

他说，潜在缺陷的存在“不是因为这不是问题的正确组合而没有出现”是可能的研究途径。新利18备用贝尔说，1968年在伦敦公寓大楼发生了部分渐进式崩溃，当时气体爆炸炸毁了承载着负载的墙壁，降低了一部分，并突出了结构性的弱点。

这座136个单位的尚普兰塔南部（Champlain Towers South）于1981年完成，由Nattel Construction建造，Nattel Construction是由Project共同开发人员Nathan Reiber拥有的迈阿密海滩建筑承包商。根据2014年在线的一座在线，他还在未来几年建造了附近的两座建筑物，即北部111个单位的尚普兰塔楼和99个单元的尚普兰塔东部。obituaryandThe Real Deal。Nattel is listed as inactive, noted a state Division of Corporations listing.

Miami-Dade Mayor Cava said on a June 27 CBS News appearance that Surfside's building inspector "did not find anything to cause concern" in an inspection of Champlain Towers North. But city Mayor Charles Burkett told ABC News that “an army of engineers are going to get in there and pore over that building from top to bottom.”

在尚普兰（Champlain Towers）南部完成时，尚未更改美国建筑法规以防止逐步崩溃。贝尔说，那是同一年发生的一个在佛罗里达州可可海滩的构建公寓项目的“著名失败”发生了这一事件，这有助于促使代码变更。

他说：“从一开始就存在一些潜在的潜在缺陷。”“通常是使建筑物降低的因素的结合。”

A crane removes wreckage of a partially collapsed building in Surfside north of Miami Beach, Florida on June 25, 2021. - Four people are now known to have died in the collapse of an oceanfront apartment building near Miami Beach, officials said Friday, while the number of unaccounted for has risen to 159 -- fueling fears of a much higher death toll.
Photo by EVA MARIE UZCATEGUI/AFP via Getty Image
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其他Possible Collapse Causes

可能会研究的其他可能原因包括建筑系统的恶化或现场条件中的变化。

据报道Miami Herald。That process mandates that a registered engineer or architect submit a report on the “general structural condition” of the building, and of its electrical systems.

6月25日，Surfside镇发布public records与尚普兰塔有关，包括结构现场调查报告conducted in 2018 that sheds light on the building's likely condition at the time of the collapse.

佛罗里达州Surfside的Champlain Towers公寓建筑的部分崩溃造成的损害。
摄影作者：Jeff Greenberg/Universal Images通过Get图像组
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The report, prepared by structural engineer Frank P. Morabito, founder and president of Sparks, Md.-based Morabito Consultants Inc., noted that the structure's parking garage—positioned underneath the tower structure—showed "abundant cracking and spalling of varying degrees ... in the concrete columns, beams and walls." The report said "although some of the damage is minor, most of the concrete deterioration needs to be repaired in a timely fashion."

The consultant made no mention that the deterioration he witnessed could potentially lead to a collapse but he said "the failed waterproofing below the pool deck and entrance drive as well as ail of the planter waterproofing is beyond its useful life and must all be completely removed and replaced."

Morabito重申，“失败的防水正在对这些区域下方的混凝土结构板造成重大结构损害”。

He said: "Failure to replace the waterproofing in the near future will cause the extent of the concrete deterioration to expand exponentially."

在6月26日的一项夜晚，结构工程师证实，尚普兰塔塔（Champlain Towers South Condominium Association）保留了该建筑物的40年重新认证，并指出“为“提供专业设计和检查服务”的“四十年经验”结构范围，包括高层住宅和商业物业。

Morabito noted on its website its involvement in devising ways to strengthen concrete in the 15-story Dolphin Towers in Sarasota, Fla., where extensive structural damage was found in 2010, forcing a 24-hour evacuation of 117 units and a five-year closure and repair.

该公司表示，该公司于2018年10月向协会提供了报告，其中包括“对进行大规模维修的可能费用进行的910万美元估计”。新利18备用官网登录莫比托说：“除其他外，我们的报告详细介绍了混凝土中的重大裂缝和破裂，这需要维修以确保居民和公众的安全。”

The engineer said "the association engaged our firm again in June 2020 to prepare a 40-year 'Building Repair and Restoration' plan with detailed specifications for completing the necessary repairs and restoration work."

It noted that "at the time of the building collapse, roof repairs were underway, but concrete restoration had not yet begun."

"We are deeply troubled by this building collapse and are working closely with the investigating authorities to understand why the structure failed."

搜索and Rescue personnel work at a partial collapse building in Surfside, Miami Beach, on June 24, 2021. - A high-rise oceanfront apartment block near Miami Beach partially collapsed early Thursday, killing at least one person and leaving 99 unaccounted for, with fears the toll may rise much higher as rescuers comb through the rubble.
Photo by CHANDAN KHANNA/AFP via Getty Images
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'Highly Aggressive Environment'

The Miami area’s climate poses a unique threat to buildings, according to John Pistorino, a principal at Pistorino & Alam Consulting Engineers Inc., South Miami, who as a consulting engineer for the county, was instrumental in developing the recertification program following the 1974 collapse of a federal building that was attributed to corroded reinforcing steel.

“We’re in a highly aggressive environment, where salty ocean air and rain can affect concrete that’s not properly protected,” says Pistorino, a 54-year engineering veteran. He likens salt to “a cancer,” especially if it gets into cantilevered balconies found on many high-rises, or in garages where columns interact with floor slabs and pile caps.

“换发新证程序确保所有者投资in proper maintenance needed for these conditions,” he says, adding that while concrete restoration work needs to be designed and completed to American Concrete Institute standards, the discovery of more serious issues during inspections can warrant a building’s immediate evacuation.

While Pistorino hesitates to speculate on a cause for the Champlain Towers collapse, he, like Bell, considers the speed of the destruction “unique” and “unheard of” in the U.S., given that concrete failures are rarely so sudden.

他说：“混凝土具有一种重塑其负载，至少将其从一个元素转移到另一个元素的方法，至少是暂时的。”“您通常会看到裂缝或其他迹象的证据。”

当搜救人员在碎片堆上工作时，可鸟瞰图显示了在迈阿密海滩北部Surfside的Champlain Towers South Collapse地点的基本足迹。
Chandan Khanna/AFP通过Getty Images摄影。
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Pistorino declined to confirm to ENR local reports that he hasbeen retainedto investigate the collapse.

岩土技术条件也可能是一个促成因素。佛罗里达国际大新利18备用学环境学院教授西蒙·沃文斯基（Shimon Wdowinski）进行的一项2020年研究，已经挑出了尚普兰塔楼的著名土地沉降。

根据release从FIU开始，土地和海平面上升研究“确定了12层的尚普兰塔楼南公寓是障碍岛东新利18备用侧的一个地方，从1993年到1999年发现了土地沉降。”但是，Wdowinski指出，仅凭因素“可能不会导致建筑物的崩溃”。