/**
  * Renvoie les ponts sur les rivières de la collection
  * @param RiviereCollection $rivieres
  * @return InfrastructureCollection
  */
 public static function getPontsDeRivieres(RiviereCollection $rivieres)
 {
     if ($rivieres->count() == 0) {
         return new InfrastructureCollection();
     }
     $req = "SELECT * FROM infrastructure WHERE ";
     $prem = true;
     $req .= ' ( ';
     foreach ($rivieres as $riviere) {
         /** @var Riviere $riviere */
         if (!$prem) {
             $req .= ' OR ';
         }
         $req .= " ((idHexa = " . $riviere->getIdHexa1() . " AND idHexa2 = " . $riviere->getIdHexa2() . ") OR (idHexa = " . $riviere->getIdHexa2() . " AND idHexa2 = " . $riviere->getIdHexa1() . ")) ";
         $prem = false;
     }
     $req .= ") AND idType=" . Infrastructures::PONT . ";";
     return DbHandler::collFromQuery($req, 'Infrastructure', 'InfrastructureCollection');
 }