Deterioration Prediction of Urban Bridges on Network Level Using Markov-Chain Model

Table 4

Number of valid data records.

Decay process	Bridge components	Time interval
		2004	2005	2006	2007	2008	2009	2010	2011	2012
		2005	2006	2007	2008	2009	2010	2011	2012	2013
Decay 1	Deck system	627	859	879	1058	1227	1161	1153	1276	1366
	Superstructure	785	1094	1149	1227	1359	1386	1393	1410	1361
	Substructure	866	1133	1185	1309	1391	1480	1449	1499	1565
Decay 2	Deck system	700	1036	973	1140	1252	1199	1224	1311	1461
	Superstructure	834	1132	1186	1275	1375	1397	1414	1442	1396
	Substructure	877	1144	1191	1313	1392	1481	1456	1502	1567

Decay 1: natural decay; Decay 2: conventional recoverable decay.