A Manual for Assessing Safety Hardware (MASH)-compliant Test Level 4 (TL-4) concrete bridge rail was optimized to satisfy MASH TL-4 design loads, maximize vehicle stability, minimize installation costs, and mitigate the potential for deck damage by minimizing loads transfer to the deck. Additionally, the bridge rail was designed with a 39 in. installation height so that it would remain crashworthy after future roadway overlays up to 3 in. thick. The barrier had a front face with a 3-degree slope from vertical to promote vehicle stability during impacts while also providing some slope to allow for slipforming installations. Yield line theory was utilized to design both interior and end regions of the barrier. Further, minimum deck strengths were determined and a deck overhang design procedure was provided for users desiring to modify their existing deck details. Finally, MASH Test 4-12 was conducted on the new bridge rail to evaluate its safety performance criteria, damage to the barrier and a critical deck configuration, and its working width. In test 4CBR-1, the 22,198 lb single-unit truck impacted the concrete bridge rail at a speed of 57.6 mph and an angle of 16 degrees. The single-unit truck was successfully contained and redirected, and all safety performance criteria were within acceptable limits as defined in MASH. Therefore, test 4CBR-1 was determined to be acceptable according to MASH Test 4-12. Conclusions and recommendations for implementation are provided.

一个手册评估安全硬件符合（MASH）标准的测试级4（TL-4）混凝土桥轨经过优化，可满足MASH TL-4设计载荷，最大程度地提高车辆稳定性，最小化安装成本并通过最大程度地减少传递至甲板的载荷来减轻甲板损坏的可能性。此外，桥轨的设计安装高度为39英寸，以便将来的车道覆盖层厚达3英寸后仍能保持防撞性能。障碍物的正面与垂直方向成3度倾斜，以提高碰撞过程中的车辆稳定性，同时还提供一定的倾斜度以允许进行滑模安装。屈服线理论用于设计屏障的内部和末端区域。此外，确定了最小甲板强度，并为希望修改其现有甲板细节的用户提供了甲板悬垂设计程序。最后，在新的桥轨上进行了MASH测试4-12，以评估其安全性能标准，对护栏和关键甲板结构的损坏以及其工作宽度。在测试4CBR-1中，这辆22,198磅的单体卡车以57.6 mph的速度和16度的角度撞击混凝土桥轨。单辆卡车成功地被收容并重新定向，所有安全性能标准均在MASH定义的可接受范围内。因此，根据MASH测试4-12确定测试4CBR-1是可接受的。提供了执行的结论和建议。198磅的单体卡车以57.6英里/小时的速度和16度的角度撞击混凝土桥轨。单辆卡车成功地被收容和转移，所有安全性能标准均在MASH定义的可接受范围内。因此，根据MASH测试4-12确定测试4CBR-1是可接受的。提供了执行的结论和建议。198磅的单体卡车以57.6英里/小时的速度和16度的角度撞击混凝土桥轨。单辆卡车成功地被收容和转移，所有安全性能标准均在MASH定义的可接受范围内。因此，根据MASH测试4-12确定测试4CBR-1是可接受的。提供了执行的结论和建议。