Innovative nail laminated timber-concrete composite floor deck system

在过去的10年里，已经进行了大量的研究，对复合木地板系统的发展，包括混凝土板和木梁连接使用剪力连接件。这种复合系统的一个稍微不同的版本是使用交叉层压木材（CLT）或结构复合木材（SCL）甲板插入梁和混凝土板之间。这种改进的概念起源于压型钢板-混凝土板组合体系，这是广泛应用于大跨度楼盖结构。木甲板用作混凝土板的模板，并减少混凝土板的厚度。由于CLT和SCL的成本相对较高，因此这种2层甲板系统的经济性令人望而却步。** 在这项研究中，将开发一种更具成本效益的2层甲板系统，由异型钉层压木材（NLT）面板和钢筋混凝土板组成。异型NLT面板是通过用更深的木材钉2 × 3（38 mm × 63 mm）木材制成的。在结构上，异型NLT可以提供抗剪键，以增强与混凝土板的复合作用，特别是在横向方向上。** 从生产的角度来看，这种甲板系统可以使用简单的工具生产，如射钉枪和夹具，以及未充分利用的2x 3木材资源。研究的第一阶段将开发最佳的产品形式和施工细节。 木材和混凝土的基本组成部分将由相对低级的材料组成。两名博士生将在前3年从事该产品开发阶段的工作。 在第3年年底，预计将解决以下参数：1。适合NLT的钉入模式; 2.最佳NLT型材几何形状，由交替的2x 3和更深的木材组成; 3.在混凝土和型材之间使用轻型紧固件的适当机械剪力连接件NLT; 4.用于连接相邻桥面板的适当详图; 5.最大楼面跨度潜力。** 第二阶段将在第四年和第五年进行，将调查两个问题。第一个将是2层甲板系统和支撑木梁或钢梁之间的连接细节。重点将放在使用重型紧固件，如钢销。第二个要研究的问题是2层桥面系统本身的振动性能以及由2层桥面和支撑梁组成的完整楼板系统的振动性能。对于大跨度楼盖系统，振动舒适度很可能决定结构设计，因此研究楼盖系统的振动性能是非常重要的。本阶段将由2名硕士学生进行。如果该项目的结果显示甲板系统具有潜在的商业可行性，则将进行一个更全面的项目，该项目将开发更精细的制造程序，并检查其他性能问题，如火灾和声学。

A substantial amount of research has been conducted over the past 10 years on the development of composite timber floor systems consisting of a concrete slab and timber beams that are connected using shear connectors. A slightly different version of this type of composite systems is to use a cross laminated timber (CLT) or structural composite lumber (SCL) deck inserted between the beams and concrete slab. This modified concept originated from the profiled steel-concrete slab composite system which is widely used in long-span floor construction. The wood deck serves as formwork for the concrete slab and reduces the thickness of the concrete slab. The economics of such a 2-layer deck system is prohibitive due to the relatively high cost of CLT and SCL. ******In this research a more cost-effective 2-layer deck system consisting of a profiled nail laminated timber (NLT) panel and a reinforced concrete slab will be developed. The profiled NLT panel is fabricated by nailing 2 by 3 (38mm x 63mm) lumber with deeper lumber. Structurally, the profiled NLT can provide a shear key to enhance composite action with the concrete slab, especially in the transverse direction. ******From the production perspective, this deck system can be produced using simple tools, such as nail guns and clamps, and an under-utilized resource of 2x3 lumber. The first phase of the research will develop the most optimum product format and construction details. The basic components of lumber and concrete will consist of relatively low-grade materials. Two PhD students will work on this product development phase in the first 3 years. At the end of year 3, it is expected that the following parameters will be resolved: 1. Suitable nailing patterns for the NLT; 2. Optimum NLT profile geometry consisting of alternating 2x3 and deeper lumber; 3. Suitable mechanical shear connectors between concrete and profile NLT using light fasteners; 4. Suitable details for connecting adjacent decking panels; 5. Maximum floor span potential. ******In the second phase, which will be conducted in years 4 and 5, two issues will be investigated. The first one will be the connection details between the 2-layer deck system and the supporting timber or steel beams. Focus will be on the use of heavy duty fasteners, such as steel dowels. The second issue to be investigated will be the vibrational performance of the 2-layer deck system on its own and that of the complete floor system consisting the 2-layer deck and supporting beams. It is important to study vibrational performance because it is well known that for long-span floor systems, vibration serviceability likely governs the structural design. This phase will be conducted by 2 MSc students. If the results from this project show potential commercial viability for the deck system, a more comprehensive project, which will develop more refined fabrication procedure and examine other performance issues such as fire and acoustics, will be pursued.