This is the conclusion of the Global Built Asset Wealth Index, which examines roads, airports, power plants, residential housing, shopping malls and other structures across 30 countries.

　　The research shows that in 2012 the United States ranked first globally in built assets, totaling $39.7 trillion, with China a close second at $35.4 trillion.

　　The study was led by British real estate and construction firm EC Harris with assistance from the Center for Economics and Business Research. It shows that China is rapidly catching up with the United States and could become the world's largest built asset nation as early as 2014.

　　As an alternative economic indicator for gauging the relative strength of different countries, the Global Built Asset Wealth Index quantifies the infrastructure and public and private properties of various nations. According to the research, China's built asset investment is expected to grow at an average rate of 6.1%, meaning that by 2022 China's total built asset value will more than double from last year's $35.4 trillion to $75.7 trillion.

　　Compared with developed economies such as Europe, emerging markets are growing faster, with Europe's built asset growth expected to be around 2.7% over the next decade.

　　As concerns grow over China's excessive reliance on investment, worries about an asset bubble in China are also rising, so the news that China will soon replace the United States as the largest built asset nation may not be universally welcomed. Although China has taken measures to reduce investment's contribution to GDP, investment's share of growth still rose from 51.2% in the first half of last year to 53.9%.

　　The research shows that fears of an impending crisis may be somewhat overblown. According to the study, China's investment growth rate is basically reasonable relative to the size of its economy.

　　The research indicates that, compared with other countries, China's investment in built assets does not appear to be excessive. In 2012, China's built asset stock was about 286% of gross domestic product (GDP), compared with an international average of about 284%. This suggests that claims of overinvestment in China may be inappropriate, at least for now. But if investment continues to grow at the expected rapid pace, the problem of overinvestment will become increasingly worrisome.

　　China's built assets per capita appear far from overbuilt levels, which may catch the eye of Chinese property developers and government officials looking for reasons to invest. In 2012, China's built asset wealth per capita was only $26,000, ranking 24th in the world and slightly more than one-fifth of the US level. The research shows that by 2022, China's built asset wealth per capita will still be 61% lower than that of the United States.

　　Of course, if the bubble bursts, the valuation of China's built assets could fall sharply, both in absolute terms and per capita.