Vital problem, occurring in the operation process of bearing timber structures, is improvement of their durability in conditions of aggressive environment. Another aspect of this problem is the increase of fire resistance of timber-steel structures. One of the possible design solutions of this problem is given in the research work. The aim of the research is study of experimental arch with support joints on glued-in steel rods. The arch was developed based on typical timber-steel arch with span length 11.8 m. Geometric shape and sizes of the arch were kept without changes, but steel elements were replaced by timber elements. Design features of the arch and calculation methods, taking into account bearing capacity of the joints on glued-in steel rods, are given in the research work. The experimental arch showed enough reliability during the test and stiffness during transportation and mounting. The arch loading was carried out in laboratory bench by using hydraulic jacks. The load increased until the arch destruction. Deflection and deformation of glued-in steel rods were measured during the test. Information about vertical deformation in the arch and stretching tensions along the length of the rods under the load were obtained in the test results. The results show that shear tensions in the joints spread along the bonding length unevenly and they have maximum value on the surface of timber elements. The arch showed perceptivity of practical using in the mild chemical-aggressive conditions and bearing structures with high requirements office resistance.