Complex sentence: The 2900 ft span replaced the low-level Westham Bridge which had been built as a toll bridge in 1911, and had been subject to flooding and was inadequate for traffic in the growing suburban area.
Split into simpler sentences: The 2900 ft span replaced the low-level Westham Bridge which had been built as a toll bridge in 1911. The old bridge was subject to flooding and was inadequate for traffic in the growing suburban area.