Compared with normal concrete, ultra high-performance concrete (UHPC) is of increasing interest for bridge engineering because of its superior tensile strength, compressive strength, and significantly enhanced durability. The creep and shrinkage effect have a significant influence on the long-term behavior of UHPC. However, the existing research on the time-dependent behavior of UHPC is still limited. In this research, based on numerical integration method, the ABAQUS user subroutine for simulating creep and shrinkage of both normal concrete (NC) and UHPC were developed by the recursive algorithm of adjacent stress increment in the time history. The accuracy of developed user subroutine was validated by creep and shrinkage test of reinforced NC beams. Subsequently, the long-term creep and shrinkage test of UHPC specimens was conducted with stress to strength ratio of 20%, 30%, and 40%, respectively. Based on the test results and the CEB-FIP Model code 1990, the simplified design formulas for predicting creep and shrinkage of UHPC were proposed respectively based on the developed UHPC material. In the proposed design formulas, the final shrinkage strain was 145 με, and the final creep coefficient was 0.46 for the developed UHPC specimens based on the test environment condition. The comparison between the test result and proposed formulas indicated good applicability and accuracy of the proposed formulas. Based on the developed ABAQUS user subroutine and the proposed design formula for creep and shrinkage, the finite element (FE) models of RC beam and UHPC beam were developed. The influence of creep and shrinkage on the long-term mechanical behavior of simply supported prestressed beams were investigated.

与普通混凝土相比，超高性能混凝土（UHPC）具有卓越的抗拉强度，抗压强度和显着提高的耐久性，因此在桥梁工程中受到越来越多的关注。蠕变和收缩效应对UHPC的长期行为具有重大影响。但是，关于UHPC的时间依赖性行为的现有研究仍然很有限。在这项研究中，基于数值积分方法，使用时程中相邻应力增量的递归算法，开发了用于模拟普通混凝土（NC）和UHPC的蠕变和收缩的ABAQUS用户子例程。通过增强型NC梁的蠕变和收缩试验验证了开发的用户子程序的准确性。随后，UHPC试样的长期蠕变和收缩试验分别在应力强度比为20％，30％和40％的条件下进行。根据测试结果和CEB-FIP型号代码1990，基于已开发的UHPC材料，分别提出了预测UHPC蠕变和收缩的简化设计公式。在建议的设计公式中，根据测试环境条件，所开发的UHPC试样的最终收缩应变为145με，最终蠕变系数为0.46。测试结果与提出的公式之间的比较表明，提出的公式具有良好的适用性和准确性。基于已开发的ABAQUS用户子程序和拟议的蠕变和收缩设计公式，开发了RC梁和UHPC梁的有限元（FE）模型。