The Lightest Beam Method - A methodology to find ultimate steel savings and reduce embodied carbon in steel framed buildings
The Lightest Beam Method - A methodology to find ultimate steel savings and reduce embodied carbon in steel framed buildings
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最轻梁法 - 一种找到最终节省钢材并减少钢框架建筑中隐含碳的方法
DOI：
10.1016/j.istruc.2020.06.015
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发表时间：
2020
期刊：
影响因子：
4.1
通讯作者：
Drewniok M
中科院分区：
文献类型：
--
作者：
Drewniok M
建筑碳强度与材料选择有关，但更重要的是材料体积。建筑结构框架本身在50年内产生了20-30%的全寿命碳。一旦我们建造净零碳运营建筑，这个数字将翻一番。因此，材料使用中的碳节约是减少建筑物对环境影响的关键。最近的研究表明，建筑结构框架中高达40%的材料可以成功移除，而不会影响设计规范的合规性。建筑物这种不必要的过度设计部分是由于缺乏结构优化，以及设计师接受保守的适用性假设，这些假设代表了减少建筑物中隐含碳的“低挂水果”。本文研究了钢框架建筑，以确定截面优化可以实现的碳节约，因为这是最容易实现的优化形式，而无需改变楼板系统和梁布局。为此，发展了研究建筑物中非复合通用梁（UB）构件的液化梁法（LBM）。根据欧洲规范选择最轻的截面，我们可以节省26.5%的钢材，一半的梁由正常使用极限状态（SLS）控制。如果使用可变载荷计算挠度，则SLS控制的梁的比例下降到31.1%，从而额外节省2.2%的质量。对于较低的固有频率假设（3 Hz）和使用平均值而不是特征钢屈服强度，可以实现最高的钢材节省34.5%。在这种情况下，由SLS控制的梁的质量比例下降到19.7%。根据现有的案例研究，发现框架中可以节省1/3的钢材，这相当于建筑物60年来初始隐含碳的36%或全寿命碳的5%。
Building carbon intensity is related to material choice, but more importantly, material volume. The building structural frame itself is responsible for 20–30% of whole-life carbon over 50 years. This figure will double once we build net-zero operational carbon buildings. Carbon savings in the use of materials are therefore he key to reducing the environmental impact of buildings. Recent studies have shown that up to 40% of material in building structural frames could be successfully removed without affecting design code compliance. This unnecessary overdesign of buildings is in part due to a lack of structural optimisation, and acceptance by designers of conservative serviceability assumptions that represent the “low hanging fruit” of reducing embodied carbon in buildings. This paper examines steel frames buildings to determine the carbon savings that can be achieved for cross-section optimisation, as this is the most accessible form of optimisation, without changing the floor system and beam layout. For this purpose the Lightest Beam Method (LBM) was developed that studied non-composite universal beams (UB) members in buildings. Choosing the lightest section with the Eurocodes we can achieve 26.5% of steel savings by mass, with a half of beams governed by serviceability limit states (SLS). If deflection is calculated using variable loads, the proportion of beams governed by the SLS drops to 31.1% giving additional 2.2% mass savings. The highest steel savings of 34.5% can be achieved for lower natural frequency assumptions (3 Hz) and using the average rather than the characteristic steel yield strength. In this case the proportion of beams by mass governed by SLS drops to 19.7%. Based on available case studies it was found that 1/3 of steel in the frames could have been saved which represents 36% of initial embodied carbon or 5% of whole-life carbon for the building over 60 years.