FAKULTAS PASCA SARJANA - INSTITUT TEKNOLOGI BANDUNG PROGRAM SISTEM DAN TEKNIK JALAN RAYA COMPARISON OF PAVEMENT STRUCTURAL CHARACTERISTICS AS DETERMINED USING BENKELMAN BEAM AND FALLING WEIGHT DEFLECTOMETER
SUMMARY COMPARISON OF PAVEMENT STRUCTURAL CHARACTERISTICS AS DETERMINED USING BENKELMAN BEAM AND FALLING WEIGHT DEFLECTOMETER, Novara Nefiadi, Efi, 1990, Program Sistem dan Teknik Jalan Raya, fakultas Pasca Sarjana, Institut Teknologi Bandung. The measurement of deflection basin profiles on flexible pavements was carried out simultaneously with a Benkelman Beam, using both the TRRL transient approach in conjunction with a Curvature Meter and the CGRA rebound test method, and with a Falling Weight Deflectometer (FWD) dynamic testing method at complementary test points. The standard axle load of 8160 kg used in Benkelman Beam testing was compared with a peak load level of the FWD at 580 kpa, which provides a similar applied stress level. The deflection test methods were carried out on pavement surfaces overlaid in the past two-three years with Hot Rolled Sheet (HRS) for a number of roads in West Java. Dynamic Cone Penetrometer (DCP) testing was also used to obtain CBR values of subgrade. Several deflection parameters namely maximum deflection, Surface Curvature Index (SCI), Radius of Curvature (R), deflection at an offset distance of 1.2 m arid 1.5 in were obtained and compared. Curve fit deflection bowls obtained for the plotted points using smooth best curves expressed by LEGER & AUTRET were also considered. Pavement structural characteristics, in terms of Modulus of Elasticity, stresses and strains, were analysed using the HOGG-BURMISTER model, DCP-BURMISTER arid MIURA TOBE approaches, the YEH expression, the RUFFORD approach and several computer programs, namely ELMOD, BISAR and PAS1. The different methods resulted in some different values of structural characteristics. However, most comparisons were highly correlatable, except for relationships obtained involving the DCP tests. Good correlations were also found in relationships between deflections obtained by FWD and Benkelman Beam. As recorded elsewhere, the Benkelman Beam deflection was found to be greater than the corresponding FWD deflection, except where deflections were less than 0.4 mm. The difference can be at least partly attributed to surface creep effects. However, poor correlations were indicated in the relationships between SCI and R as obtained by the FWD and Benkelman Beam. This resulted in poor correlations between Modulus of Elasticity, stresses and strains evaluated from FWD and Benkelman Beam deflection basins. Some relatioliships between structural characteristics including SCI or R and Dmax, deflections at an offset distance of 1.2 m or 1.5 m and subgrade modulus, SCI with tensile strain, and Dmax and compressive strain were also established. iv
RINGKASAN COMPARISON OF PAVEMENT STRUCTURAL CHARACTERISTICS AS DETERMINED USING BENKELMAN BEAM AND FALLING WEIGHT DEFLECTOMETER, Novara Nefiadi, Efi, 1990, Program Sistem dan Teknik Jalan Raya, Fakultas Pasca Sarjana, Institut Teknologi Bandung. Pengukuran profit lendutan pada perkerasan lentur dilakukan secara simultan dengan menggunakan Benkelman Beam, yaitu Metoda Transient TRRL dilengkapi dengar, Curvature Meter, dan Metoda Rebound CGRA, bersama dengan pengukuran Falling Weight Deflectometer (FWD) pada titik-titik yang dipilih. Beban standar as sebesar 8160 kg, yang digunakan pada Benkelman Beam, dibandingkan dengan beban maksimum FWD sebesar 580 kpa. Pengukuran lendutan dilakukan pads permukaan perkerasan yang dilapis ulang dua atau tiga tahun yang lalu dengan Hot Rolled Sheet (HRS) di beberapa jalan di Jawa Barat. Percobaan Dynamic Cone Penetrometer (DCP) juga dilakukan untuk memperoleh nilai CBR tanah dasar. Beberapa parameter lendutan yaitu lendutan maksimum, Indeks Lengkung Permukaan (SCI), Jari-jari Kelengkungan (R), lendutan pada jarak ofset 1,2 m dan 1,5 m diperoleh dan dibandingkan. Kurva profit lendutari yang diperoleh untuk titik-titik yang dipilih dibuat dengan menggunakan persamaan LEGER & AUTRET. Karakteristik struktur perkerasan, dalam bentuk Modulus Elastis, tegangan dan regangan, dianalisa dengan menggunakan model HOGG-BURMISTER, pendekatan DCP-BURMISTER dan MIURA & TOBE, formula YEH, pendekatan RUFFORD dan beberapa program komputer, yaitu ELMOD, BISAR dan PASS. Metoda yang berbeda menghasilkan nilai karakteristik struktur yang berbeda. Perbandingan hasil di atas menunjukkan korelasi yang baik, kecuali untuk hasil yang diperoleh dengan percobaan DCP. Korelasi yang baik juga diperoleh untuk hubungan antara lendutan yang diperoleh dengan FWD dan Benkelman Beam. Hasil lendutan dengan Benkelman Beam lebih besar daripada lendutan FWD, kecuali untuk nilai lendutan yang lebih kecil dari 0,4 mm. Perbedaan ini disebabkan oleh pengaruh rangkak di permukaan perkerasan. Korelasi yang rendah juga ditunjukkan dalam hubungan antara SCI dan R yang diperoleh dengan FWD dan Benkelman Beam. Hal ini menyebabkan korelasi yang rendah pula antara Modulus Elastis, tegangan dan regangan yang dievaluasi dari profit lendutan FWD dan Benkelman Beam. Juga ditunjukkan beberapa hubungan antara karakteristik struktur, meliputi SCI atau R dan lendutari maksimum, lendutan pada jarak ofset 1,2 m atau 1,5 m dan modulus tansh dasar, SCI dan regangan. tarik, dan lendutan maksimum dan regangan teken. v