Highway bridges are very important structures in modern transportation net, so a great concern should be taken regarding bridges safety and serviceability. In the USA for example, only following the collapse of the silver bridge over Ohio River in 1967 which killed 47 people, comprehensive inspection programs for bridges had been established  . Bridges inspection is a very important factor for a rating of bridges. Several researches were conducted to find economical and effective maintenance and rehabilitation programs. Reference  developed a new method that has proven particularly suited for strengthening and stiffening reinforced and pre-stressed concrete bridge girders. It makes use of externally bonded carbon fiber reinforced polymer (CFRP) laminates characterized by lightweight, high strength and stiffness, resistance to corrosion, and good fatigue characteristics. Reference  developed a repair manual for Concrete Bridges. This study did not constitute a design standard, but suggestions to the decision maker. Reference  inspected Jilin highway concrete bridge in China. The results of the investigation showed that some concrete beams suffered from serious damages. Jacketing method, grouting repair method, replacement of expansion joints, and drainage system were the main proposed methods of rehabilitation. Reference  performed a detailed evaluation on 12 five-girder T-beam bridges in the southwestern US. They concluded that several factors were causing a failure mechanism, including a limited recognition in the original design standard of cyclic loading, high volume of heavy truck traffic, and transverse moments caused by unbalanced wheel loading. After the investigation, recommendations were made to rehabilitate these Bridges. Reference  presented the results of Non-Destructive Techniques (NDT) on the Pentagon Road Bridge, in Chatham, Kent, England. The results were used to identify the portion of the bridge which had undergone the greatest amount of deterioration. Reference  studied the influence of neutralisation reaction on 21 bridges in Taiwan. They predicted the performance degradation curve of the Bridges and the appropriate timing for repair. Reference  investigated Sorell Causeway Bridge in Tasmania, Australia. The Bridge demolished in 2002 because of the concerns about its safety in the light of the increasing size and frequency of longitudinal cracks in the webs of the beams, progressive failure of the strands in the tendons, and rebar corrosion. Reference  assessed the seismic vulnerability of 148 existing RC bridges in Algiers. They presented a simple and efficient inspection method for the preliminary evaluation of the seismic vulnerability of existing bridge structures. The intent of the current case study, which conducted on 27/3/2019, is to provide a comprehensive view of Jordanian highway Bridges which will be valuable for the Ministry of Public Work and Housing in Jordan, the Jordanian Engineers Association, and for Civil Engineering Students and Professors in Jordanian Universities. This case study can lead to building up a comprehensive Database regarding Bridges status in Jordan, in which the Bridges can be classified into categories with respect to their maintenance priority. This proposition will greatly help in avoiding Bridges accidents.
2. Highway Bridges in Jordan
Jordan is a key country in the Middle East connecting the gulf countries with the northern west countries. The dissert highway in Jordan is the main road crossing the country from Aqaba in the south to Irbid in the north, passing by the capital Amman. Most of the country and Middle East goods are delivered through this highway, specifically 89% of local goods and 32% of Middle East goods are conveyed along it according to the Ministry of Industry and Trade. Nevertheless, there is no official maintenance guide for the highway bridges in Jordan, which are located along the highway. There is even no periodic monitoring or safety check of bridges by officials. In this case study, two highway bridges near Al-Hossainea town southern to Amman will be inspected and assessed. These two highway bridges across the desert highway in Jordan are named as Al-Qadisia and Unayza-Petra bridges. The two bridges are located south of Al-Hossainea with 600 m and 6 km, that is 175 km and 183 km south of Amman, respectively.
2.1. Al-Qadisia Bridge (Pre-Stressed and Reinforced Concrete Bridge)
Constructed in 1985, this bridge is 5 m height and directed east-west, and the traffic under the bridge is from north to south in the direction to Aqaba with two lanes, and from south to north in the direction to Amman with two lanes. The over pass is two lanes, one in each direction. The dimensions and shape of the bridge is presented in Figure 1 and Figure 2.
The superstructure consists of ten pre-stressed I-beam girders (bulb girders) with 1.35 m height and 0.5 m bottom flange, with 1.2 m spacing center to center. Each girder were reinforced with four tendons, each one of them is consisting of six 7-in diameter strands, and 10 φ 25 mm reinforced steel bars at the bottom of each girder. To achieve in depth visual inspection one lane was closed for inspection and the other lane was open to the traffic. To check the strands at 5 m height, a vehicle mountain with ladder four meter height was ready to inspect the strands very closely.
Identification of the Bridge Problems:
• Concrete girders damage caused by over-height vehicle collision.
• Insufficient clearance. The bridge is only 5 m height and according to the highway police directorate, over-high trucks collided with it 117 times since its establishment.
• Inefficient drainage system. For Instance, the highway police patrols locked the traffic over and under the Bridge against hundred vehicles for more than three hours last winter, as a result of pond rainfall around the area of the bridge.
These problems can be seen clearly in Figures 3-9.
2.2. Unayza-Petra Bridge (Reinforced Concrete Bridge)
This bridge was constructed in 1989 and is directed east-west and the traffic under it is from north to south in the direction to Aqaba, and from south to north in the direction to Amman. The traffic under the bridge consists of four lanes two in each direction. The over pass is two lanes, one in each direction. The
Figure 1. Al-Qadisia Bridge (Looking West; 10 Pre-stressed girders setting on three Intermediate Piers with six columns, and two Outside Abutments. Traffic S-N to Amman East Bay, and N-S to Aqaba West Bay).
Figure 2. Drawing of AL-Qadesia bridge at AL-Hossaina.
Figure 3. Deterioration at the bottom of web of Girder No.10: sever damage in longitudinal steel reinforcement, cutting of stirrups, full concrete cover spalling, enter removal of pre-stressed duct, and heavy deterioration of strands.
Figure 4. Deterioration at the bottom of web of Girder No. 7: moderate deterioration of Strands and longitudinal main steel, and cutting of stirrups and concrete spalling, also extensive concrete cracks.
Figure 5. Girder No. 6 moderate deterioration: concrete spalling, displacement of main steel and deep cracks.
Figure 6. Sever deterioration of concrete at Girder No. 1: entire removal of concrete cover, deep cracks on the web reaching the flange, Strands cutting, main steel reinforcements and stirrups cutting.
bridge’s superstructure consists of seven reinforced concrete rectangular-beam girders, each girder has a cross section of 1.2 m × 0.5 m with spacing 1.7 m center to center, and each girder is reinforced with 12 φ 20 mm. To achieve in depth visual inspection one lane was closed for inspection and the other lane was
Figure 7. Very heavy deterioration on Girders No. 1 and 2: entire concrete spalling, heavy deterioration and cutting of strands, deep cracks along the web reaching the flange, displacement and cutting of longitudinal reinforced Bars and Stirrups.
(a) (b) (c) (d)
Figure 8. Close sight on Girder No. 1: (a), (b) Entire removal of concrete, deep cracks, also steel reinforcements, stirrups, and strands cutting. (c), (d) Complete isolation of the bottom flange from the web (Complete Failure).
Figure 9. Deterioration of Girder No. 2: cutting of steel bars, severe removal and cracks of Concrete, and heavy deterioration of Strands.
Identification of the Bridge Problems:
• Insufficient clearance.
Figure 10. Unayza-Petra Bridge (Looking west; 7 reinforced concrete rectangular-beam girders setting on three Intermediate Piers with four 0.9 × 0.9 m columns, and two Outside Abutments. Traffic S-N to Amman East Bay, and N-S to Aqaba West Bay).
Figure 11. Drawing of Unayza-Petra Bridge at AL-Hossaina.
Figure 12. Deterioration of Girder No. 1: entire spalling of concrete, heavy damage of the girder steel reinforcement, and cutting of stirrups.
Figure 13. The deterioration of Unayza-Petra Bridge girders due to collision with over-height trucks.
3. Inspection Results and Discussion
The case study resulted in a comprehensive view of the two Bridges’ conditions and provided recommendations for suitable rehabilitation techniques. All this information is shown in Table 1.
As seen in Table 1. Some girders in both Bridges are totally deficient, these girders can’t be rehabilitated due to their intensive failure. The authors advise that these girders must be replaced immediately, any delay will carry over the failure to the next girders and will cause a failure in the Bridges’ deck. If such a scenario happens, then loses in lives and costs will be huge.
Regarding the moderately damaged girders, these girders should be rehabilitated immediately to avoid damage propagation. If not, then they will keep deteriorating until they reach the severe damage case. In which, they will have to be replaced, which will increase the cost. The rehabilitation process has to be carried according to   , and  . First, the loss concrete must be removed, and then the concrete surface must be cleaned. After that, epoxy should be used to bond the old concrete surface with the newly casted concrete. This will prevent corrosion of steel reinforcement and section deterioration. As these girders’ capacity still not regained due to reinforcement buckling and cutting, FRP composites can be used to strengthen these girders. Concrete or steel jacketing have a larger size and will reduce the Bridges clearance, which will increase the problem since more trucks will collide with them until their failure. FRP laminates are very thin but effective, and their application to the girders is easier.
The minor damaged girders need a concrete cover to protect their reinforcement, so loss concrete must be cleaned and epoxy can be used to bond the new cover to the old section. Since these girders have no concrete spalling or reinforcement failure, then there is no need for strengthening composites.
4. Conclusions and Recommendations
After assessing the two bridges by the authors, who are experts in Bridges inspection with experience from the USA, the following points and recommendations are concluded:
Regarding Al-Qadisia Bridge (Pre-Stressed and Reinforced Concrete Bridge):
Table 1. Summary of the Bridges’ conditions and recommended rehabilitation methods.
*Severe damage: entire loss of concrete at the bottom, loss of duct and cutting of strands, intensive deformation of steel reinforcement, cutting of stirrups, and heavy cracks propagation starting at bottom and reaching top. Moderate damage: spalling of concrete cover, exposed tendons and rusting of ducts, deformation and corrosion of steel reinforcement, cutting of stirrups, and cracks propagation. Minor damage: spalling of concrete not more than 3 - 5 cm, appearance of rebar and duct.
1) According to the current inspection, this Bridge needs three box culverts 2 × 2 m for rainfall drainage to avoid ponding at winter season.
2) It is necessary to have clearance of 5.6 m as a minimum height to avoid collision with over-height trucks. This needs a topography surveying to achieve this task.
3) According to the current inspection, Girders No. 1, 2 on the eastern direction and No. 10 on the western direction need immediate replacement because of severe damage (the inspectors concluded that it will be less expensive than repairing and rehabilitating them by 19.6%). However this technique needs highly qualified people and high quality materials with past experience in this field.
4) Girders No. 4, 5, 6, 7 on both western and eastern sides need immediate rehabilitations.
Regarding Unayza-Petra Bridge (Reinforced Concrete Bridge):
1) It is necessary to have clearance of 5.6 m as a minimum height to avoid collision with over-height trucks. This needs a topography surveying to achieve this task.
2) According to the current inspection, Girder No. 1 on the western direction needs immediate replacement because of severe damage (the inspectors concluded that it will be less expensive than repairing and rehabilitating them by 27.1%).
3) Girders 2, 3, and 7 on the eastern direction need immediate repair and rehabilitation.