【作者】 彭长领；

【导师】 徐有邻； 刘立新；

【作者基本信息】 郑州大学 ， 结构工程， 2009， 硕士

【摘要】 预应力混凝土用钢棒简称PC钢棒,是采用低合金钢热轧盘条为原料,经机械除锈、冷拔加工成型,再经淬火和回火热处理工艺生产的一种高强钢筋。根据PC钢棒标准《预应力混凝土用钢棒》GB/T 5223.3-2005,其应具有强度高（1080 MPa～1570MPa）、延性好(δ_gt≥3.5%),可焊性、镦锻性强,可盘卷的优点。PC钢棒在生产过程中采用机械弯曲除锈,不需酸洗。因此,推广应用PC钢棒部分替代高强钢丝、钢绞线不仅可以弥补我国现阶段中等强度预应力钢筋的不足,更可减少高强钢丝、钢绞线生产过程中因酸洗而带来的环境污染,取得一定的经济、环境效益。为检验PC钢棒在中等跨度预应力空心板中应用的可能性,本试验依据《预应力长向圆孔板图集》京92G42和《混凝土结构设计规范》GB50010-2002制作了12块配PC钢棒的预应力长向圆孔板。对构件制作过程的监测分析表明,本批次PC钢棒的材性较脆,镦头性能和蒸汽养护适应不高,延性和质量稳定性有待提高。构件养护完成后,依据《预应力长向圆孔板图集》京92G42的要求进行了加载试验,全程量测了构件的挠度、裂缝宽度和裂缝数量的发展变化,并依据《混凝土结构工程施工质量验收规范》GB 50204-2002的要求进行了结构性能检验。通过试验发现,在建立有效预应力的条件下,配PC钢棒的空心板承载受力性能、恢复性能和破坏时的裂缝形态良好,且PC钢棒的强度能被充分利用,具有较好的抗裂、超载性能。但本批次试验中配置直径9.0mm的PC钢棒的空心板破坏时的裂缝宽度较小,且有脆断的危险,表明PC钢棒的延性和质量稳定性有待提高。参考有关资料,将空心板的不规则截面等效简化为“工”字形截面,并根据《混凝土结构设计规范》GB50010-2002的规定进行了预应力损失、反拱、开裂荷载、正常使用极限状态下的挠度和极限状态下的受弯承载力进行了计算,通过与实测结果的对比分析,提出了工程中可用的计算建议。最后分析了当前我国预应力空心板的主要配筋情况,并选取了四块跨度和张拉控制应力相近的配冷轧带肋钢筋,螺旋肋钢丝、高强钢绞线和PC钢棒的预应力空心板,对其承载受力性能进行了综合对比分析。更多还原

【Abstract】 The PC steel bars （Abbreviation of the steel bars for prestressed concrete） is a new prestressed steel produced through the mechanical descaling, cold drawing molding processing, and then through the quenching and heat treatment processes. The production uses the low-alloy hot rolled steel wire rod as the raw material. According to the Chinese code Steel Bars for Prestressed Concrete GB/T 5223.3-2005, the PC bar has the advantages of high strength（1080 MPa～1570 MPa）, good ductility(δ_at≥3.5%), well solderability, upsetting and reeling. The production processes of the PC bar use the mechanical bending derusting without pickling. So, promoting to use PC bar in a large scale as a substitute of high-strength steel wire, strand not only can make up the lack of mid-strength steel in our country, but also can reduce the contamination produced along with the washing by the acid in the producing process of the high strength steel wire, strand. This can acquire significant economic and environment benefits.In order to test the flexural behavior of the prestressed medium-span hollow slab reinforced by the PC bars, twelve hollow slabs reinforced by the PC bars are produced according to the Beijing stand atlas Prestressed Long-span Hollow Slab Jing 92G42 and The Design Code Of The Concrete Structure GB50010-2002. The monitoring and analysis of the production process indicates that this batch of the PC bar is brittle, bad behavior of upsetting and steam curing. So, the PC bar’s ductility and quality stability still need to be improved.After the curing is done, the load tests are done according to the Beijing standard atlas Prestressed Longspun Hollow Slab Jing 92G42 and monitored the development of the deflection, the crack width and the number of the crack along with the load increasing. Also the structural performance tests are done according to The Acceptance Code of Construction Quality GB50024-2002. Form the test results, we can get the conclusion that the slabs have a good flexural behavior, a good recovery performance and a well crack distribution after the failure of the slab when the adequate prestress is established. The slabs have a good crack resistance and overloading performance. Also it can be made full use of the PC bar’s strength.But in this tests, the hollow slab’s crack width reinforced by theφ9.0 PC bars is small, and this slabs have the risk of brittle fracture, indicating that the ductility and quality stability of the PC bar continue needs to be improved. After referring to the relevant documents, the irregular cross-section of the hollow slab is equivalent simplified as the工-shaped cross-section for analysis. After the equivalent simplifying, the prestress loss, reverse-arch, crack load, deflection under the serviceability limit state and the ultimate load are calculated according to The Design Code Of The Concrete Structure GB50010-2002. Through the comparing with the test results, the practicable advices are suggested in order to use the PC bar in the engineering.At last, this text analyzes the main reinforcements used in the prestressed hollow slab, and selects four hollow slabs reinforcedby the cold-rolled ribbed steel, high-strength steel wire,strand and PC bar, making a comparative analysis on the flexural behavior of these slabs.更多还原