基于遗传算法的板材成型过程早期凝固强度建模与仿真

在冬季,水泥预制板生产过程中存在凝固时间长,生产效率低的问题。为此根据HYDCEM模型结合实际生产过程建立了一种基于遗传算法求解水泥预制板材早期抗压强度的方法。首先根据HYDCEM模型建立水泥预制板材早期凝结强度随温度及时间变化的强度发展模型。然后利用有限差分法求解水泥预制板保温过程的动态传热情况,结合强度发展模型得到水泥预制板材各网格点强度变化数据。最后,通过遗传算法对强度评判模型进行求解,结果表明遗传算法在求解早期抗压强度过程中具有很好的适应性,建立的水泥预制板早期抗压强度模型对生产过程有很好的指导作用。

BIM-based construction technologies for precast foamed lightweight concrete wallboards

To promote the visualisation and informatisation of the construction process of precast foamed lightweight concrete wallboards(PFLCWs),from the analysis of the construction requirements of PFLCWs,three key construction technologies based on building information modelling(BIM),namely,parameterised modelling for the PFLCW layout design,drawing generation to draw the PFLCW layout and quantity statistics for extracting PFLCW quantities,are proposed.Then,a reinforced concrete(RC)frame infilled with PFLCW is considered the test model to verify the feasibility of the aforementioned technologies.The results show that PFLCW layout design can be accomplished rapidly and visually using parameterised modelling technology.The PFLCW layout diagram can be generated directly using drawing generation technology.The proposed quantity statistics technology enables the automatic export of PFLCW bills of quantities.The built parameterised model helps construction workers rapidly and intuitively understand the specific layout details of PFLCWs.Moreover,the generated layout drawing and the bills of quantities based on the parameterised model can guide the production and on-site installation of PFLCWs.The research conclusions can serve as a practical guide and technical support for PFLCW engineering applications.

薄壁钢梁-陶粒混凝土装配式组合楼板受火后受力性能研究

由冷弯薄壁钢梁和陶粒混凝土预制板组成的装配式组合楼板具有轻质、高强和施工方便等优点。为研究该类组合楼板的抗火性能及高温后的受力性能,对6块遭受温度为700℃、持续90 min烃类火灾升温作用的简支组合楼板试件进行受火后受力性能试验研究。结果表明:当施加的等效均布荷载达到2 kN/m^2时,受火作用后的组合楼板试件最大挠度小于跨度的1/400,且在加载过程中薄壁钢梁虽已明显扭曲、混凝土板多处开裂,但组合楼板试件未出现整体坍落现象;以普通栓钉为抗剪键的受火后组合楼板试件,其极限荷载比薄壁钢抗剪键组合楼板试件的提高14.2%;当用钢量相同时,主梁数量较多的组合楼板试件采用U形钢筋作为拉结件,其火灾后极限荷载比采用钢条拉结件的组合楼板试件的增加33%,且整体刚度也有所提高;该类组合楼板在受火后仍具有较高承载能力和整体刚度,且抗剪键类型、预制板之间设置的拉结件以及拉结件与抗剪键的连接方式均对其受火后的受力性能有较大的影响。引入组合效应系数可以较好地反映受火后组合楼板试件的组合效应及内部损伤程度。