... .5-6-8-12-14-16-18-20-25-30120351×10-16-20-25-4012034×4-5-6-835140×5 ... -6-7-8-9-1035159×16-18-20-22-25-3030406×10-20-25-28-35-4011045×3.5-4 ... ×8-12-16-25-30105450×10-12-14-16-20-25-34-40-5010851×3.5-4-5-6 ... -12-1440219×6-8-12-16-18-20-25110560×10-14-16-20-25-30-40-50-6012468×4-4 ... and mechanical stent, can reduce weight, save the metal 20 to 40%, but industrialized mechanized construction, roads and bridges ...