Valmiki Ramayana Ayodhya Kanda Sarga 80 Shloka 10

तदा then, नराः people, बन्धनीयान् required to be bridged, तांस्तान् at such, देशान् places, बबन्धु: bridged, क्षोद्यान् required crushing, सञ्चुक्षुदुः pulverised, भेदनीयान् च required to be split open, बिभिदुः broke them.

People threw bridges at places that needed to be bridged. They pulverised stones that obstructed the path and split open big stones to drain out water.