This paper presents the design, analysis, and experimental evaluations of precast reinforced UHPC (ultra high-performance concrete) beams with a new design concept of non-uniform flexural members. With outstanding mechanical properties of UHPC which can develop the compressive strength up to 200MPa, the tensile strengths up to 8~20MPa and the tensile strain up to 1~5%, a non-uniform structural shape of UHPC flexural beams were optimally designed using three-dimensional finite element analysis. The experiments were carried out and compared with the design strength in order to verify the performance of them. Proposed non-uniform UHPC beams were evaluated by a series of three-point beam loading test as well as estimated by design bending and shear strength of members. The newly designed UHPC beams show excellent performances not only in transverse load capacities but also in deformation capacities.

In current research, it was attempted a preliminary design and evaluation of non-uniform ultra high-strength concrete (UHSC) truss members. UHSC used here has the compressive strength of 180 MPa, the tensile strength of 8 to 20 MPa, and the tensile strain after cracks up to 2%. By the three-dimensional finite element stress analysis as well as strut-tie approach on concrete solid beams, the non-uniform truss shape of UHSC truss was designed with the architectural esthetic concept. In a series of examples, to compare with conventional concrete members, the proposed UHSC truss members have advantages in capabilities of the slender design with minimum weight with high performances under transverse loadings as well as the aesthetically non-uniform design for spatial structures.

본 연구에서는 일반적으로 사용되는 직사각형 부재 대신 초고강도 콘크리트를 적용하여 비정형 형상으로 제작된 구조부재를 설계 하였다. 비정형 형상으로 부재를 실험체를 제작하기 위해 80-200MPa의 높은 압축강도, 10-20MPa 인장강도와 1.0-5.0%정도의 고인성인장변형률을 가진 초고강도 콘크리트를 사용하였다. 또한 정확한 비정형 형상을 제작하기 위해 비정형 거푸집 기술을 새롭게 고안하여 적용 검토하였다.

This research was an attempt to design a new structural concept of non-uniform reinforced and super concrete truss members applying by super concrete which has the compressive strength of 80-200MPa, the tensile strength of 8-20MPa, and the tensile strain of 1.0-5.0%. The super concrete truss members were designed by the Strut-Tie approach as well as aesthetic design concept. The structural performance of designed superconcrete truss was evaluated with the conventional reinforced concrete members.