February_1967 — Page 33

(v) The Joint ASCE-ACI Commit- tee оп Composite Construc- tion,(9)

after a collective ana- lysis of the available experi- mental data (including Han- son's), recommended the fol- lowing values:

At working load: -

On smooth interface with minimum steel

lb./in.2

40

On rough interface with minimum steel lb./in.2

Minimum steel requirement

160

vertical ties of an area equal to 0.15% of the in- terface, at a spacing not exceeding 4 times the depth of the in-situ con- crete nor 24".

(When additional steel ties are used, the permissible horizontal shear stress on a rough interface may be in- creased at the rate of 75 lb./in.2 for each additional area of steel ties equal to 1% of the contact area.) At ultimate load: Twice the

values at working load. (vi) A.A.S.H.O. Specification:(17)

At ultimate load:- On smooth interface with minimum steel 75 lb. in.2

On rough interface with minimum steel

lb./in.2

150

On rough interface with steel in

excess of the

minimum 225 lb. in.2 Minimum steel requirement same as in (v).

(vii) AC1318-63(18);

At working load:- Same as in

(v), except that on a rough interface without any me- chanical anchorage, the permissible horizontal shear stress is reduced to 40 lb./in.2

At ultimate load:- 1.6 times the values at working load.

(viii) CP116(19);

At working load:— Same as in

(vii).

References

"Precast-pre- bridges: 2.

1. Hanson. N.W.:

stressed concrete Horizontal shear connections": Journal of Portland Cement As- sociation Research and Develop- ment Laboratories, Vol. 2. No. 2. May 1960. pp. 38-58.

2. Samuely, F.J.: "Composite method of prestressed concrete (prestressed soffits with cast-in- place topping)"; Paper B-36, In- ternational Congress of Pre- stressed Concrete, Ghent, 1951. 3. Graf, O. & Weil, G.: "Decken aus Fertigbauteilen": Bulletin No. 119, 1955, Deutscher Auss- chuss fur Stahlbeton. Berlin. 4. Meyer, A.: "Die Verbundwir- kung zwischen Stahlbetonfertig- teilen und Ortheton": Der Bau-

}

Crack pattern in composite T-beam

TII

71

才

Horizontal shear failure in composite T-beam

P+

TII

Instrumentation for measuring horizontal slip and vertical separation at interface of composite T-beam

5. Gessner, M.: "Berechnung der Bugelbewehrung in Stahlbeton- verbundkonstruktionen mit vor- gespanntem Zuggurt": Betons- tein-Zeitung, No. 2, Feb. 1957, pp. 101-106.

6. Özell, A.M.: "Behavior of sim- ple-span and continuous com- posite prestressed concrete beams": Journal of Prestressed Concrete Institute, Vol. 2, No. 1. June 1957, pp. 18-31.

7. Kaar, P.H., Kriz, B. & Hog-

nestad, E.: "Precast-prestressed concrete bridges: 1. Pilot tests of continuous girders"; Journal of Portland Cement Association Research and Development La- boratories, Vol. 3, No. 1, Jan. 1961, pp. 19-46.

8. Mattock, A.H. & Kaar, P.H.:

9.

"Precast-prestressed concrete bridges: 4. Shear tests of con- tinuous girders": Journal of Portland Cement Association Research and Development La- boratories, Vol. 3, No. 1, Jan. 1961, pp. 19-46.

"Tentative recommenda- tions for design and construction of composite beams and girders for buildings": Progress Report of Joint ASCE-ACÍ Committee on Composite Construction; Proceedings of American Society of Civil Engineers, Vol. 86, No. ST12, Part 1. Dec. 1960. pp. 73-92.

10. Evans, R.H. & & Kong. F.K.:

"Shear connections for composite prestressed beams": 7th Con- gress. International Association for Bridge and Structural En- gineering, Rio de Janeiro. Aug. 1964; Preliminary Publication. pp. 797-802.

ingenieur, Vol. 26. No. 11, Nov. 11. Chung, H.W.: Research data not

1951. pp. 327-330.

Far East Architect & Builder February, 1967

yet published.

12. Samuely, F.J.: "Some recent ex-

perience in composite precast and in-situ concrete construction. with particular reference to pre- stressing": Proceedings of Institu- tion of Civil Engineers. Part III. Vol. 1. Aug. 1952. pp. 222-259. 13. Evans, R.H. & Bennett, E.W.: "Prestressed Concrete Theory and Design": Chapman and Hall, London, 1958.

14. Division of Roads and Road Traffic (Southern Rodesia): "Standard Specification for de- sign and supply of pretensioned concrete bridge beams for cul- verts and small bridges"; Pre- stress (Journal of South African Prestressed Concrete Develop- ment Group), Vol. 9, No. 4. Apr. 1960, pp. 29-37.

15. Rühle,

H.: Vorschlage fur Bemessung und Konstruktion von Betonverbundkonstruktionen mit schlaffer oder vorgespannter Bewehrung": Bauplanung-Bau- tecknik. Vol. 12. No. 5. 1958. pp. 201-206, and No. 6. June 1958, pp. 267-268. 16. Saemann, J.C. & Washa, G.W.:

May

"Horizontal shear connections between precast beams and cast- in-place slabs": Proceedings of American Concrete Institute, Vol. 61, 1964. pp. 1383-1408. 17. American Association of State Highway Officials: "Standard Specification for highway bridges"; 8th edition, 1961. 18. American Concrete Institute: ACI Standard 318-63 "Build- ing Code Requirements for Re- inforced Concrete": ACI Book of Standards, 1963. 19. British Standards Institution: British Standard Code of Practice CP116:1965 "The Structural

Use of Precast Concrete.”

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