Double corrosion protected DYWIDAG bar anchors secure a new highway in Trabzon

Slope stabilization for a new highway in Trabzon, Turkey

Trabzon located on the eastern shore of the Turkish Black Sea is one of the oldest cities of the world. A newly developed highway will relieve the growing congestion traffic through the historic district.

The highway designers took precautions not to change the appearance of the historic district. In many locations, this highway wound its way over steep slopes over slender bridges or cuts supported by retaining walls near the boundary of the historic old town. The tallest retaining walls constructed using 15° inclined drilled piles were tied back with rock anchors and permanent tie back anchors. The retaining wall anchors reduce the bending moment at the retaining wall foundation, which is a proven and economic method for slope stabilization.

The General Highway Department awarded phase 2 of the complex slope stabilization project to the Turkish General Contractor ÖZ Insaat A.S. with headquarters in Ankara. The rock anchors and permanent tie back anchors were specified as DYWIDAG bar anchors 36mm dia. St 835/1030 with double corrosion protection. The design service load for these anchors is approximately 500kN in accordance wit the German DIN Code.

Special steel pipe structures were needed to secure the double corrosion protected DYWIDAG bar anchors in the backfill areas. These steel pipes protected the plastic anchor sheathing against damage from falling rocks used for back filling.

A total of 600 anchors were supplied with a combined length of 12,000m and a weight of 125tons.