Fire Performance of Timber-Concrete Composite (TCC) Systems in Mass Timber Buildings

在一个充满了制造由工程木材制成的大型木材型材的可能性的新时代，即，胶合层压木材（胶合木）、交叉层压木材（CLT）和钉合层压木材（NLT）部分，这些部分的强度和结构完整性可以在火灾中保持更长的时间。因此，世界各地越来越多地建造主要由木材建造的高层建筑。这种建筑物中的地板系统甚至可以被制造得更坚固并且跨越更长的距离，以允许设计者在楼层平面方面具有更大的通用性，并且通过添加由混凝土制成的顶层来促进现代建筑物中的开放式概念设计，该顶层允许使用足够的剪切连接来形成木材-混凝土复合（TCC）地板系统。在该复合系统中，有效地利用了两种材料的有利机械性能，因此，如果与木材地板（例如仅由CLT或NLT面板制成的那些）相比，可以实现更坚固的地板系统的若干优点。在使用TCC地板系统的几个优点中，有更大的强度、耐久性和更好的声学和振动性能特性。 不幸的是，TCC系统在火灾条件下的实验工作并不像在环境温度下那样广泛，因此一个非常重要的领域，值得进一步研究的是TCC地板系统在火灾条件下的行为，重点放在某些方面。例如，以前对TCC楼板系统的大多数实验研究都是小尺寸、小数量和/或代表单向楼板组件;而在拟议的研究计划中，将在火灾条件下检查二十四（24）个采用CLT和NLT板的大型双向TCC板式楼板组件。此外，这是非常罕见的找到研究，解决板间联合连接的TCC地板系统的结构防火性能的影响，因此，这些测试组件与CLT板将包括花键面板到面板连接。此外，使用由胶合木梁制成的支撑框架系统沿着TCC楼板的周边，以增强火灾中混凝土板的膜作用，这是迄今为止在现有文献中从未提出过的。因此，我们相信，所提出的研究计划将导致：发展新的和可靠的实验数据和可能的实施模式，TCC板式楼盖系统在火灾条件下，在未来版本的CSA O 86标准（科学影响）;开发能够模拟火灾条件下具有选定剪力连接的TCC楼板组件的实际行为的有限元模型该项目的目标是：通过开发新的设计模式间接支持加拿大木材工业（经济影响）;为加拿大人提供更坚固、可持续的材料制造和防火安全的大规模木材建筑（社会影响）。

In a new era full of possibilities for manufacturing large timber sections made of engineered wood, i.e., glued-laminated timber (glulam), cross-laminated timber (CLT) and nailed-laminated timber (NLT) sections, strength and structural integrity of such sections can be retained for much longer time in fire. As a result, several tall buildings made primarily of timber are increasingly being constructed worldwide. Floor systems in such buildings can even be made stronger and span longer distances to allow designers greater versatility in terms of floor plan and promote for open concept design in modern buildings by adding a top layer made of concrete that allows the formation of Timber-Concrete Composite (TCC) floor systems with the use of sufficient shear connections. In this composite system, the advantageous mechanical properties of both materials are efficiently utilized and thus, several advantages can be achieved for a more robust floor system, if compared to timber floors such as those made solely of CLT or NLT panels. Among the several advantages of utilizing TCC floor systems are greater strength, durability, and much improved acoustics and vibration performance characteristics. Unfortunately, experimental work on TCC systems in fire conditions is not as extensive as at ambient temperature, and thus one very important area that warrants further investigation is the behaviour of TCC floor systems in fire conditions with focus on certain aspects. For instance, most previous experimental studies on TCC floor systems were of small size, small number and/or representing one-way floor assemblies; whereas in the proposed research program, twenty-four (24) large-scale two-way TCC slab-type floor assemblies utilizing CLT and NLT panels will be examined in fire conditions. Also, it is very rare to find research studies that address the effect of inter-panels joint connections on the structural fire behaviour of TCC floor systems, and thus those test assemblies with CLT panels will include spline panel-to-panel connections. In addition, the use of a supporting framing system made of glulam beams along the perimeter of the TCC floor slab to enhance the membrane action of the concrete slabs in fire is something that has never been presented in the available literature so far. Therefore, it is believed that the proposed research program will lead to: development of new and reliable experimental data and possible implementation of design models for TCC slab-type floor systems in fire conditions in the future version of CSA O86 standard (scientific impact); development of FE models that can simulate the actual behaviour of those TCC floor assemblies with the selected shear connections in fire conditions (technological impact); indirectly support the Canadian wood industry through the development of new design models (economic impact); and allow more robust, sustainable material-made, and fire safe mass timber buildings for Canadians (social impact).