Al Manar's coverage of the event appears to be a reprint of a story published in the pro-opposition As-Safir daily on Monday. While the report goes on to highlight the propaganda value of the project, namely how work on the bridge allegedly went on under the watchful eye of the IDF in al-Ghajar, it's important to take note of what has been a larger ongoing trend developing on the ground in Lebanon.
The country's government has long had the image of being unable to adequately maintain roads and provide for public works. The destruction left in the wake of the 2006 war to the country's infrastructure has perhaps only further opened the door for ‘outsiders’ to fill in this gap. In fact, the al-Ghajar Bridge is supposedly just one of hundreds of projects that the Iran has set out to undertake in Lebanon. For a complete listing of the bridges and overpasses being reconstructed, and their corresponding donors, see here.
The Iranian foundation is among a host of other international organizations involved in projects in Lebanon. While a number of international NGOs – funded by the UN, EU, US etc. – are primarily heading relief and development work in the country, the Iranian foundation is mainly involved in heavy infrastructure projects. In fact, It's quite common to see signs (like the one in the image above) throughout the country marking where the ICRL has done its work, especially in pro-Hezbollah areas.
Therefore, one might conclude that Iran may seek to advance its image in the eyes of Lebanese by undertaking these projects. At the same time, by improving the infrastructure in south Lebanon, others might argue this is only intended to enhance Hezbollah's ability to mobilize and maneuver its forces against Israel. Either way, by investing in reconstruction projects there's perhaps plenty of opportunity for Iran to enhance both its hard and soft power capabilities in Lebanon.