An experimental and analytical study on 15 specimens of lap splices embedded in nonconventional concrete without confining reinforcement was performed under direct tension. The experimental program involved two groups of straight‐ended and anchored‐ended bars; three different techniques were employed with different splice lengths. For straight‐ended bars, conventional lap splice was studied as a benchmark. The anchored‐ended steel bars were hooks, hooks intersecting with cross bars, and plate‐end bars. It was found that, the used techniques not only achieved higher tensile stress at failure, but also different modes of failure were observed. Besides, a splice length of five times bar diameter was found to be sufficient to achieve the nominal yield stress of the reinforcing steel bar in the case of anchored‐ended bars. Finally, an analytical model was proposed in order to predict the ultimate tensile stress of the straight‐ended spliced bars. The accuracy of the proposed model was verified against the test results of 137 existing specimens from previous research. The comparison showed good agreement between the results of the proposed model and the test results.

中文翻译：

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不同技术在非常规混凝土中拉力搭接的试验与分析研究

在直接拉力作用下，对15个非常规混凝土中埋置的搭接接头的标本进行了实验和分析研究。实验程序包括两组直端钢筋和锚端钢筋。三种不同的技术采用了不同的拼接长度。对于直杆，以常规搭接接头为基准进行了研究。锚定的钢筋是钩子，与横杆相交的钩子和板端钢筋。发现，所使用的技术不仅在失效时获得了更高的拉伸应力，而且还观察到了不同的失效模式。此外，发现锚固端钢筋的接头长度是钢筋直径的五倍，足以达到钢筋的标称屈服应力。最后，为了预测直端拼接钢筋的极限拉伸应力，提出了一个分析模型。对照先前研究的137个现有标本的测试结果验证了所提模型的准确性。比较结果表明，所提出模型的结果与测试结果吻合良好。