Minimum span in feet for I-Beams 34 X depth of beam in inches.

Minimum span in feet for Channels = 1⁄2 X depth of channel in inches.

Standard Connections for Steel Beams to Cast Iron Columns. Cast iron is weak in bending. It it therefore necessary that heavy lugs should be used under the seat of each beam. It is equally important to see that the end of the beam rests on the seat.

Following is a set of standard connections for beams framing into cast iron columns. These connections are in

common use.

For 4-5-6-7′′ beams. For 8"-9"and 10"beams.

Fig. 34.-Standard Beam Connections to Cast Iron Columns. All lugs are to be 1 in, thick except where otherwise noted. All holes drilled for 34 in. diam. bolts.

I. Uses.

CHAPTER XIII.

Sidewalk Beams.

These beams are intented to support the sidewalk over the vault area, as well as the metal door frames used for stairwells and ash-hoists openings. In addition sidewalk beams will also brace the top of the street retaining walls against the steel columns of the main structure. Guide rails of ash-hoists and other sidewalk elevators are often kept in line by the sidewalk beams.

2. Loading. All sidewalk framing must be designed to carry not less than 300 lbs. live load per square foot. By using roughly 400 lbs. per sq. foot for sidewalk loading, this will allow for both the dead and the live load. While this loading is seldom realized in practice, it is nevertheless essential for safety, when we consider the fact that heavy merchandise boxes are often dumped on edge from express wagons upon the sidewalk. This also shows why considerable care must be given to all connections of sidewalk beams.

It often happens that such beams are only at first put in an approximately correct position and then bolted temporarily, and the erector may or may not have the intention to go over these connections before the job is finished. The masons and floor arch people will often cover the top and sides of some of the connections before all the bolts have been put in. Only constant inspection will secure good work.

3. Framing. Sidewalk beams are usually wall bearing at one end and bolted to the main steel work at the other end. When these beams are not riveted to the main structure, they may be removed whenever necessary to allow for the passage of boilers or elevator machinery from the street into the cellar. Instead of this, several beams near the centre of the first tier may be left temporarily bolted, without floor arches in between and covered with planks, until all necessary boilers and machinery has been lowered into the cellar.

At this time it often happens that the steel contractor will refuse to bolt any such beams for the second time, while mechanics who have temporarily removed them to lower their machinery or boilers will often not put all the bolts back and will seldom make them tight. Connections of such interior beams can be inspected more readily than connections in the front of the building, as the latter are often covered with

brick work before being inspected. Having in view the importance of good permanent connections in case of all sidewalk beams, it is reasonable to specify and insist upon having sidewalk beams riveted to the columns, whenever possible. While the Code gives no specific information on this point, whenever the the approved plans specify that all column connections must be riveted, this provision should be enforced also in case of connections of sidewalk beams to columns. Connections of small framing beams in between the main sidewalk beams may be bolted.

DEFECTIVE WORK. Following are a few examples of more or less common occurrence in sidewalk framing.

I. Incorrect Elevation. The beams may be set too high or too low. In one instance the sidewalk had an easy continuous slope along the whole fifty feet of frontage. One end of this front building line was four inches higher than the other. It happened that the surveyor did not notice this difference in elevation and he considered the building line and the curb. line as being level. He started the work from the low point. Then came the iron erector and set his grillage and other members using the high end of the building line as his starting point. The result was that all the sidewalk beams were set too high and nearly all of them had to be reset. This required drilling new holes and resulted in defective connections, which had to be carefully reinforced.

2. Slope. All sidewalks in Manhattan must be raised from the curbstone in the proportion of 2 inches in 10 feet, under the penalty of $10 (Art. III., Sec. 118, City Ordinances). This slope is usually formed by lowering the outer ends of the steel beams in the same proportion; when necessary, the same slope may be obtained by using an extra fill in the sidewalk material and sloping its top surface as required while the steel beams are set level. This, however, could not be done when the first tier beams are set too high.

3. Wrong Setting. In some cases several sidewalk beams were set upside down. In the shop all tie-rod holes were punched 3 in. from the top. Under the conditions, some tie-rod holes came 3 in. from the bottom. All the beams that were upside down had to be unbolted and turned in their proper position, thus bringing all tie rod holes in a level line 3 in. from the top. Otherwise new tie rod holes would have to be drilled in those beams.

4. Anchors and Plates. The outer end of most sidewalk beams bear on the retaining walls. At this end steel templates and 3/4 in. government anchors or other good anchors

should be provided. These anchors are sometimes left out where the beams have considerable bearing and on a short span. This however is against the Code and against good practice and is not met with in first class work. Where there

is a possibility that government or other loose anchors may be stolen or omitted, architects may specify bolted or riveted anchors consisting of two knee angles attached to the end of each beam.

5. Vault Framing. Sidewalk beams are often used to support a vault roof over an area. According to Art. VI., Section 186, of City Ordinances, every description of opening below the surface of the street in front of any shop, store, house or other building, if covered over, shall be considered and held to be a vault or cistern within the meaning of said article. A grating or open iron work used to connect an entrance to the sidewalk by spanning over an area is not a vault; also openings used exclusively as places for descending to the cellar floor of any building or buildings by means of steps must not be considered as vaults. (Art. VI., Sec. 187, City Ordinances). Also, vaults must not extend further than the line of the sidewalk or curbstone (Art. VI., Sec. 173, City Ordinances).

Before a vault is built, a permit must be secured from the Bureau of Highways. Such permits are granted only after the payment to the City of a sum varying between 30 cts. and $2 per sq. ft. of vault area, depending upon location. But permits for vaults in public highways are in the nature of revocable private easements which can be fully enjoyed until revoked by and at the pleasure of the Board of Aldermen.

It sometimes happens that vaults are put up without a permit. This is a violation which may be prosecuted and a penalty of $100 or more may be enforced. In addition a permit may be refused, in which case the whole vault must be taken down. Cases of erecting vaults without a permit are reported to the Bureau of Buildings by either construction or iron inspectors; thence the cases are usually referred to the Bureau of Highways for prosecution.

6. Old Vaults. It often happens that old buildings having vaults are demolished to make room for new structures. It is reasonably presumed that any vault which has existed for a number of years has been originally constructed with the consent of the municipal authorities. It is therefore not necessary to ask for a new permit or to pay a new vault fee as long as the old vault is not demolished. However, when an old vault is taken down and reconstructed a new permit must be secured, as demolishing a vault will automatically