Considering the magnitude of the fault rupture movements and the significant ground shaking, both in terms of accelerations and velocities, the engineered structures on the highway system fared quite well. Damage to the bridges was restricted to an area south-southeast of Sakarya (Adapazari), as shown on the map included in Figure 1. In this area, two main highways run west-east, parallel to the Anatolian Fault. This segment of E80, also known as the TEM (Trans European Motorway), goes south to Ankara, beyond the effected area. It is a four-lane divided toll road. The E100 (the old main highway) is a two-lane road, which continues in the easterly direction. Several overpasses crossing the E80 sustained minor damage in the form of pier tilting (arising from ground movement), cover concrete spalling of the decks at movement joints, and approach fill settlement. Such damage did not substantially impair the use of the main highways or the roads traversing these highways over the motorway.

 Figure 1. Damage to traffic structures

One overpass crossing the E80 at Artifye did collapse (see Figures 1 and 2). This was not surprising as the fault rupture passed directly beneath the bridge. The fault movement exceeded the available seat width, causing the span to collapse. In so doing, it dragged the remaining three spans off their seats, as shown in Figure 3. One of the spans collapsed onto a passing bus, killing 10 people.

Figure 2. A collapsed overpass crossing the E80 TEM at Artifiye
(Click on photo to enlarge)

(Click on photo to enlarge)

Problems were also encountered with four highway bridges crossing the Sakarya River. Most notable was the bridge carrying the westbound lanes of the E80 Motorway. The ten-span bridge is shown in Figure 4. It consists of ten 40 m simply supported prestressed concrete trough shaped girders seated on laminated elastomeric bearing pads. Shear keys are provided at the end of each box to inhibit transverse and longitudinal seismic movements; the elastomeric bearings accommodate thermal movements. The apparent large impulsive fault-normal ground shaking coupled with vertical accelerations caused the shear keys to fail in several spans and unseat their bearings. This is also shown in Figure 4. The westbound bridge had to be closed to traffic for repairs. The eastbound sister bridge sustained less damage to the shear keys and only partial walk-out of the bearing pads; complete unseating did not occur and the bridge has remained fully operational.

(Click on photo to enlarge)

 Figure 4. The east (left) and west (right) bound bridges over the Sakarya River. Note shifting of the spans and the unseating of the bearings in the westbound bridge. The bearings on the eastbound bridge have partially "walked out,"  but not unseated.

Damage to the E80 was caused by surface rupturing, settlement of engineered roadway fills and the settlement of bridge and culvert approaches (see Figure 3). The extent of damage to the engineered fills on the E80 Motorway extended some 10 km to the west and east of the Sakarya area. Settlements ranging from 100 mm to 500 mm were observed, as shown in Figure 6. This damage did initially hamper the movement of emergency services equipment and supplies. Repair of the damage was accomplished quickly in two stages. The first stage consisted of removing damaged portions of the pavement, grading and asphalt patching. This stage was completed within the first few days following the earthquake. A 50 km/hr speed restriction was imposed. The second stage included resurfacing a 50 km section of the motorway. This work was completed within 18 days following the earthquake and traffic is operating normal, at a speed of 120 km/hr.

(Click on photo to enlarge)

Figure 5. Arial view of surface faulting across E80 Motorway

(Click on photo to enlarge)

Figure 6. A typical view of the bump-onto-the-bridge on the E80 Motorway. Up to 500 mm embankment settle- ments were common over a 20 km stretch of road. Notice the guardrail in the photograph as further evidence of the embankment settlement.

 Minor damage to other transportation facilities, as indicated in Figure 1, has had a minimal effect on traffic. Two long viaducts near Koreez and Duzce were undamaged. The undamaged viaduct near Duzce had been originally outfitted with energy dissipation devices. Initial inspections indicate that seismic movements were arrested by the energy dissipation devices.