Page:Popular Science Monthly Volume 88.djvu/48

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WO bridges that use the same right-of-way present a study in economy that may be seen at Pasadena, California. Both bridges are of reinforced concrete, and both are for vehicular travel, each entirely independent of the other. The small bridge, running lengthwise, is directly underneath the large one, and, in fact, its approach at one end passed through two of the piers of the larger structure.

The large bridge, completed about two years ago, was constructed at the combined expense of the city of Pasadena and the county of Los Angeles. It has a total length of one thousand, four hundred and seventy feet, and is composed of nine spans and six girder spans, besides the usual abutments. From the lowest point in the channel bed to the roadway level it is one hundred and sixty feet in height, and the roadway that traverses it is twenty-eight feet wide, with a five-foot sidewalk on either side. Extending across what is known as the Arroyo Seco, from rim to rim, it spans not only a small mountain stream, but also a lowland of considerable extent, embracing many acres of orange groves and a number of fine homes. It is a feature of a muchtraveled automobile road that connects Pasadena with the city of Los Angeles, and is of rather ornate design.

The small bridge, finished only recently, was built at the expense of private property party owners. It is composed of one long span and two short ones, and, including approaches, is about three hundred feet long. Built directly underneath the large one, it is designed to bridge the stream channel only. Owing to the skeleton-like construction of the piers of the great structure overhead, one of its approaches passes through one of these piers, and the roadway leading thereto pierces still another. The purpose of this small bridge, thus located, is to serve the property owners who reside on the level below the rims of the depression, so that they may not be required to make the long and circuitous climb to and from the larger bridge's approaches.

TWENTY-FIVE MILLION gallon concrete tank which will be liidden from view by being parked over, probably the largest of its kind in the world, has been constructed in Cleveland as a part of the new filtration plant. The plant will have a capacity of one hundred and fifty million gallons a day. It covers fifteen acres.

When completed the tank will be covered with earth and become a part of the city park on which the plant is being erected.